Most 38 Plymouths used a 16 x4 rim.  37s had three slots between the centre and the outer rim , all others had 4.  Dodge USA used a different brake drum so the wheels had less offset. There are lots of 16 inch rims out there as trucks used them up to about 1960 but truck wheels and Chrysler /Desoto wheels are generally 4 1/2 inches wide.

I know the 38 Plymouth coupe came with several rim sizes. Can anyone tell me what
rim width, offset and backspace was standard for the 16 and 17 inch rims? I'm trying to
get replacement replica type wheels for my 38 coupe (Coker wheel/tire combination).