(4/19/2020 9:30:38 PM)
Congrats on your barn find purchase. Hopefully you will have a lot of fun restoring it.
The two letters after 44 in the serial numbers up through sometime in 1952 denote the fuel type (first letter) and tractor configuration (second letter). In your case, the DR stands for Diesel Row-crop. A 44 DS would be a Diesel Standard. Similarly a 44 KR would be a Kerosene Row-crop, 44 GS would be a Gasoline Standard, and so on. The fuel for LP tractors was denoted as Butane. So an LP Row-crop would be 44 BR.
Hope this helps.