I have never seen shoes stick to drums on these old cars. Every case I've seen is wheel cylinders.
Wheel cylinders siezing up is a typical problem with old cars that are not driven very often. Especially in parts of the country where there are temperature and humidity extremes. The original cylinders are cast iron but the pistons are aluminum so if they sit and there's any moisture, you get the electrolysis going and they "weld" together. It can happen in as little as a few months depending on the relative humidity.
I can almost say with certainty that this is the issue you're having. Last year I had a wheel cylinder that was seized up so badly, I had beat it out using the biggest hammer and drive punch I have and it still was difficult.
As far as removing those hubs goes, they need to be shocked off. A drum puller will not do the job. It's best to use a hub puller like this one -
I've seen this type for sale on ebay a few times.
I connect it, then put a peice of flat iron I have between the axle end and the spindle on the puller (to act as buffer), tighten it good, then hit the end of the puller shaft/spindle with the biggest hammer you've got. You may have to do it a few times but it will come off.
Since it's only the rear wheels, it could also be that your parking brake is stuck. If you don't use the parking brake, then this would not be the case but if you've pulled it then released it, the front cable may have released but the rear could be stuck, hence keeping the shoes spread out against the drums.