Most claim the WD did not come with the "duel fule" Ensign Gasoline/ LPG carb. However, the WD/WD45 parts book lists 70226076 as the Carburetor, combination (ensign no 2554) as for the WD, and 70226714 as the Carburetor, combination (Ensign no. 3060) See link.
Now, from what I"ve seen, to find either of the ensign cabs listed, you will likely need to part with a large part of your wallet. And even if you do manage to find one, no one on this form seams to know what to do if you need to rebuild it.
Search the archives of the allis board here for Ensign MG1 and you will find some about the Ensign carb we have with a WD45. I didn"t re read what is posted there, but if the LP carb you have is stamped MG1 where it bolts to the manifold, it is the same LP carb as used on the D series AC"s.
Hope that helps you some.