Fuel injection, like the supercharger, was invented back in the teens. I don't know why it wasn't adopted earlier, but suspect it wasn't perfected to the level of the carburetor and the price of fuel kept it from adding value. The GM 50's fuelie units didn't help the image. At the same time, they tweaked carb design about every year until the use fell off.
Turbocharging was another invention that should have been in common use, based on efficiency, HP gains, etc. It was in use only in heavy engines. We wouldn't have had all the gas consumption that we had(aka oil addiction), if it had been adopted earlier, now today's "eco boost". But the stories go, the oil guys were in cahoots with the detroit boys - scratching each others back. Back in the day, there were always stories/rumors about a patent or patent holder for mileage improvement being "bought out" by GM. Packard may have also fell to some Big 3 "tactics", like Tucker, etc. But that's like the Yeti and UFOs, more mythology than proof.

I agree with the comments.
I illustrate people are asking a bit low, also. A excellent survivor should bring as much or more than a fresh resto.

This months Hemming's. A restored 23 rd, spent >$60K asking $34K competing w/ an excellent original selling less than $20K.

Schematic is right. After it comes out the muffler, there's a rubber hanger. Then it routes over the rearend to a hanger off the frame rail by the trunk cross member the tail pipe clamps to. It runs inside the frame rail between gas tank and exits below the bumper. If it doesn't fit exactly, it's probably bent wrong. "C" bend is vertical over the rearend. I got my trunk pan and gas tank out with new exhaust still on, but won't be back in the garage for pix until Tomorrow night, if you need more info.

www.autocolorlibrary.com doesn't seem to list the Packard colors past '53. You can try them by phone.
DuPont would have the codes, but you have to be a registered auto business to get on their site or contact a DuPont distributor directly.
Did you check this site/literature for '56 color chips?
If you can get the Packard paint code number and manufacturer they should be able to cross it. Otherwise, without documentation, it might be made for or by whomever shot the last paint and non-standard.
Metallics as stated above are subject to the spray conditions and may not look the same even if the formula is correct. A good paint shop can match metallics by adjusting pressure, thinning, spray angle, # coats, etc. Do test panels first.

I'm going stand corrected/update myself, they're making a 6v replacement LED bulb according to superbrightleds.
Some cars require a LED flasher.
It's changing fast. So it's extremely simple now, plug and play.

If just dust remains, fluid has long since leaked out.
It's a safety system, so as above, a complete system check is necessary not optional.
My opinion: These early booster brakes are problems waiting to happen and not reliable for today's driving. Rebuilding only prolongs the inevitable. But necessary for authenticity, but not for daily driving.

FYI: just a suggestion. If you're having voltage drop off at idle, you might consider testing the voltage regulator(VR) and battery. You might be able to adjust the voltage regulator to a higher cut out voltage or may have to replace VR and/or battery or some wiring.
If a generators spinning it's capable of making current but the regulator tells it what to do with it. Things degrade with time. Contacts and wires oxidize etc, that changes the characteristics. Batteries lose ampacity and terminal and wire corrosion increases resistance dulling performance.
Caution: If you set VR too high you'll cook the battery. Follow the recommended procedure.

I had to buy a set off ebay for another brand auto because wiperman didn't have any.
The thread size is 6x40 not 6x48 as posted previously.

Almost anything electrical is possible, but not always cost effective. I suggest you have to analyze how badly you want/need to do that and what's driving the need?
Is it the non-working or poor condition of the current lights or something else? Right now, I know of no, off the shelf, answer. You'd probably have to engineer it yourself, so it's a skills question too. I recently saw some LED replacement bulbs coming on but don't remember but don't think they fit these bases. The automotive market is competitive and year/model based so it's not easy to get engineering specs for modifications as it is in other markets.
As Howard mentions, the LEDs have much less amp draw which saves energy by not producing heat. The old systems were designed/depended on higher amp draw. So it's the time/cost of repair vs the time/cost to upgrade.
I'm sure myself and the forum readers would be happy to hear your methods and results.
ps; I'm going non-stock and still looking at taillight options. I had a custom design then changed my mind after I had to integrate back-up lights and there weren't many complimentary options. Since my stock lenses are perfect, recessing and flushing them is one option under review but requires alot of hours to remake the whole base assy. I'm using small LED's for marker lights and elsewhere but will be 12V system.