i just purchased a farm that came with an allis chalmers tractor, wd45 i was told. i'm trying to figure out what actual model it is and the year it was made. the casting stamps on the rear end say 6-18-49 and the 5 digit serial number (wd 26661) seems to indicate from what i can find that it's not a wd45 but actually a wd made in 1949. BUT the tractor has wd45 decals AND more importantly the snap coupler hitch which i thought started in 1953/54. was the snap coupler hitch ever made as a retro-fit for the older models? i love the tractor and want to restore it but just want to make sure what it really is. any help or info would be greatly appreciated!