Paul,
Whether or not they were sold with Handisacs had more to do with level than time. The top-of-the-line model 60 had the Handisac and was built from 1940-42, but the mid-range model 26 and economy 305 from the same era both had cloth shake-out bags. The top-of-the-line model 61 had the Handisac and was built from 1946-50, but the 27 (1945+6) and the 28 (1946-50) had cloth shake-out bags. The 62 was built from 1950-53 and had the Handisac, but the 29 built at the same time did not.
I don't think Hoover offered a conversion bag for the lower end models, as the Handisac would have been an incentive to buy the top-of-the-line models, but I do know that aftermarket conversions were eventually offered by companies such as DVC, Dust Care, and Essco. Some of them, like the one on my 29, were a pretty good match.
Jeff