Could you double check that serial number? The last 1955 was serial number 253 050, and it was built in 1974. The White 2-105 replaced the 1955 after that.

I don't think your 1955 is a 1974 either, as they had switched to 699 on the model # by that time. If you have the hydraulic cooler pump that is by the injection pump and drives off a single belt from the front of the crankshaft, then it is 1973 or older.

As to how many were made, I haven't dug through those production numbers yet, but I will someday. If it is like all of the other FWAs I have researched so far, not many.