According to TO 00-25-29 and TO 00-45-1 Blade 6491A-0 was used on the 23E50-473 props on the C-46A-CU (but not on the C-46A-HI) in 1943 but I do not have a reference to later dash numbers of this blade. Certainly later C-46s may well use it. The earlier blades were 6477-12.
There may have been a Navy use also but the above TO's only cover USAAF aircraft
Interestingly the two C-46-HI aircraft were built by Higgins - a boat builder - and the prop type is not identified