Not truly Packard but for anyone interested in the subject, ran across a fairly decent book on early thru late 60's auto AC units. Most are aftermarkets with a couple of early brand X factory experimental unit designs pictured.
Packard and Bishop & Babcock is credited with the first really successful unit in 39. Book also provides some insight on the divergent approaches others were doing and what might have been if Packard had not had their successful intro.
About 160 pages in paperback form. $20 thru Amazon. Too bad the photos are all B&W non glossy but still interesting to see some of the units and components available at the time.