[autoradiotech]

These radios were the same electrically, the differences were in the mechanical fit and the cosmetics. The model numbers you listed are the Philco model numbers, the Chrysler/Mopar numbers were 3 digit in the 800 series; P-5106=812, D-5107=813 etc. After 1950 the 'P' prefix indicates Plymouth not Packard as Packard Went to Delco radios during 1950. In the postwar models the first two digits indicate the model year, 51=1951 there were no 52 Chrysler models as the 51's were carried over into 1952 with no changes. Hope this helps you out.