Bit of advice needed.

In all my youth's wisdom i asked for a Mamiya RB67 Pro S body which i saw on ebay for Christmas. Cracking price it was bought for as well. Now i need some wisdom from you guys.
1. When the shutter is pressed, the mirror goes up fine, nice and smooth, but it doesn't quite go past the lens mount hole. Can it be ajusted? Is it quite a difficult job and will i have to send it off?
2. Is there anywhere that will tell me years and serial numbers?
3. Will the 220 film back fit both 120 and 220 film or just 220?

Many thanks in advance.
Andy.

Right i now know that the 120 and 220 film backs don't take each other's type of film, unless they are the motorised backs.

I would suggest you have the camera serviced...it would be well worth it as you'll have years of usage from it. Besides, the money that was saved on it's purchase...will more than pay for the service!