Wow - this is great information. Thanks for all of the replies!
I did uncover the engine number and that number does match it exactly. As Mike B mentioned, it does look hand stamped. This definitely confirms the engine build date.
The truck does not have a driver's side cowl, only passenger side so that along with the vent windows and pull-down handles would also point me to a '51 body.
Before I bought it, the truck appears to have have been modern-titled first in Arizona the briefly in Texas with the door sticker attached in Arizona. The number was assigned by the AZ DOT and is not an engine number. The evidence from both titles show it as a 1949. The number from the Arizona sticker was transferred to my Ohio title.There are no other original plates. The Arizona sticker may be covering the holes from the original.
The lettering on the front bumper are very faint and difficult to get a good photo of but as near as I can tell are AMG GAFB. It's been a long time since I served but I thought the vehicle numbers back then had numbers and unit identifications. My original thought was the "AFB" stood for Air Force Base.
I purchased the truck back in '95 and drove it just locally for about a year. It never ran that great and I parked it, planning to get back to when I had the time. I hear the comments all the time from other old guys that the time just slipped away - and here we are 27 years later! After retiring this year, I decided to get the truck back on the road but found the 216 locked up. After tearing it down a bit, I finally freed it up. I do however have a 235 that I had professionally rebuilt back in the '90s that I plan on replacing the 216 with. Since my auto mechanical experience is limited, II've already found awesome information on this forum that is helping me go through the process of the swap. Thank you all again