You'll have fun with your new toy. It's a wonderful machine and a work of art to look at.
Be careful with the mirror. What is hanging that mirror may just be old sticky foam. You can replace that yourself one rainy afternoon. Get the self stick foam from MicroTools. An assorted pack is around $25 and has all the thicknesses you'll ever need. Get the USA stuff it's a better quality.
Carefully scrape off the old foam with a dental pic. Go around the mirror and at the top of the mirror box, just under the view screen where you'll see a strip and 2 bumpers. One side is thicker than the other so you'll have to make up the difference by layering the foam. It is higher on one corner than the other by about 1mm. Cut the stuff with a razor or scalpel.
Once you get the foam you will want to do all the backs. your old 35mm cameras and the neighbors' cameras and god only knows what other things you'll come up with, I did my enlargers too. Get a repair manual and do the internal seals as well?
Good luck, be gentile with the 30 yr old Russian tank. It'll be around for many years to come with just a little care, we'll still be taking pictures of all those ddigital cameras and printers in the dumps 30 years form now.
PS The bellows will straighten itself in time just by what you did. If they are not leaking light the wrinkel will not make any difference in the images.
Good luck.. if you have any questions feel free to e-mail me directly at AUTOMAX1@JUNO.COM