" . . did they [4 1/2" wheels/rims] come on later model trucks than this? [1941]"

Scott,

Yes

The 4.5" rim was optional during most Advance-Design years (1949-1955-1st series) and was optional until after 1955-1st series. The 4.0" wheels were standard until 1949.

When the 15 inch rim became standard in 1956/56 Task Force Trucks, the 6.50x16 was then a popular option.

If you want to use your year's hubcaps, be sure to look for rims with hub cap clips.