1982 Chevy Corvette Window Motor Problem!

I asked my grandparents to take there prized car off there hands because they are getting old.

story is when I drove it home with my son the right window went down but couldnt go up.

so we decided to take the nice panel off and looked around on the internet for some help to see what the problem was but found nothing to help.
we had a person of a chevy dealership say you gota knock out the rivits and get the motor out.

well we did that and we guess its shot.( 20+ year old car all stock) it just doesnt have the power anymore.