Looking at the exploded views and parts list, I note the following differences:
Model 22 looks like a very simple direct-drive reel with no gears or drive train. The parts list describes a "drive shaft and thumbing disc", which I interpret use as a drag.
Model 44 has a raised cover over a gear drive, push-button line release and a crank handle.
I see an introduction date of 1954, have no info on length of production. Since Century 100 was introduced the following year, I'd think it was surely in the design stage when these reels were made. The Sidewinder 60 (1952) and 80 (1953) were actually more sophisticated designs, I wonder if 22 & 44 might have been an effort to use up remaining Sidewinder parts before Century launch.Posted for Skip Smith.