Another thought, or two...
If you have a replacement bellows, and if you are ready to replace it, with some thought you could use contact cement. A number of non-Polaroid folders I took apart had a layer of some semi-rigid fiber with a clearance hole to pass the lens/shutter body, to flatten the front of the bellows against the back of the front folding standard.
A small number glue the bellows to the standard. I found that contact cement come off very easily with some brand (I can't remember) of automotive "Bug & Tar Remover", so I would consider gluing it reversible. Now a vinyl bellows I would hesitate to subject to solvents and adhesives.
I was able to remove the back door & roller assemblies from several old rollfilm Polaroids
but cannot recall satisfactorily finding how to remove an old belows.