Try these references. You are correct about the place where you have the ? is a letter for the month, A=Jan, B=Feb, ...

http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsmA5.htm

http://chevy.oldcarmanualproject.com/chevyresto/5052.htm

You may be able to research that website for more info.

I guess there was a typo error sometime in the past, and some previous owner had a new plate stamped to match the VIN on the title... Alot can happen in 60+ years. Good luck.


Professional Novice