I had tried to post a picture of the parts list for my 270 that shows the removable gear , but the server didn't like the file for some reason .
And yes , I'll bet that production cost probablly figured into the change . In looking at the shaft in Hobbsy's picture , the non removable pinion of the 300 does indeed look different from the 270's gear . The 270 also employed an "index pin" in the gear setup as well , so they eliminated two parts by making the crank and gear as one unit ...