Were Choate dozer blades rare?

I have a 6U D4 with one on and may part out the pump in front of the radiator. Leo

I don,t think they would be call rare. AC used some of them and not unusual to see one on an old crawler around.

I don't think they were. RG Letourneau seems to be the pioneer of earthmoving equipment, and there were others that got into building dozer kits for track type tractors, LaPlante-Choate, I believe was a significant manufacturer, Bucyrus Erie and other similar manufacturers did the same, and you will find they were fairly common for a time. At some point all the tractor manufacturers started building their own, but if you look at WWII tractors, they wore most of what was being built then and LaPlante-Choate dozer kits were fit to many tractors due to the overall demand, no one manufacturer could keep up with production, so if you look at depot and staging area photos, loaded with tractors headed to their destinations, many had other than the more common LeTourneau dozer kits installed. I also believe that LaPlante-Choate, was a forerunner in hydraulic dozer kits, most in WWII were cable control, but there were a fair amount with hydraulic dozer kits, the old war photos depict this clearly. I've got one technical manual for a hydraulic LaPlante-Choate dozer kit for a Caterpillar D7 tractor, December 1946, R-75 side dozer. Great thing about this book, is besides the technical information, there is also lots of information instructing how to use a dozer blade, much if not all of it is still true today, just that angle and tilt are not manual functions to adjust LOL !

I doubt this helps any;
AC bought LaPlant-Choate Mfg. Co. in 1952

Might be getting a litle more rare. Awful lot of them got scrapped out around here.