[joetx]

All very good info. Thankyou guys very much. I am sure my first digit after the "star" is a "9" and the only digits I'm not sure off is the 2nd and 3rd. They look like a "7" and "1", and what I'm not seeing is the "top" of the digit, I can see the bottom, so these are probably a "9" and a "T". I'm going with the prefix "99T". Again, thanks a lot. Joe.

Originally Posted by rotorwrench

A 1941 truck could have been 19T prefix unless they continued 99T from 1939. The CCC or Civilian Conservation Corps may have purchased the vehicles on a contract basis which could have carried through from the year of the contract like the wartime trucks did. Most trucks for wartime were ordered on a 1942 contract until close to the end of 1944 and early 1945 when they had to start new contracts.

Also, Mercury continued the 99A prefix even after the war so it may be more likely the trucks bigger than 1/2 ton did as well.