You would need to remove the pad from the stock (typically held in place with Philips head screws). The bolt is a metric hex-head socket (5mm I think).
There MAY be a problem - some of these bolts were held into the stock and are a bear to remove (if this is the case be careful - if you put too much pressure on the bolt you can damage the stock) - others will just slide out. There should be a washer or large bushing (depends on the bolt length) and then there should be a rounded cup shaped washer directly under the head of the bolt - this lets the bolt apply pressure perpendicularly to the stock.
I can tell you from personal experience that you must, I repeat must be careful when putting the new stock on as they use different lengths of bolts. I put a stock on my 686 that came off another 686 and the bolt screwed into the trigger assembly. It was not good. I used a 12 inch 1/4 inch extension and 6 mm hex socket. Nothing to getting the stock off. As mentioned above, hang on to the receiver. I would recommend putting the receiver into a vise and then you can gently pull the stock loose as you unscrew the stock bolt. Jackie B.
The transfer should not be a problem. Should drop right in if new hole is the right size. Make sure there is no more than 3/8in of the bolt sticking through the new hole or it will bend your trigger assy and prevent proper function when you tighten reciever to new stock. I hope I understood your question correctly and gave you a good answer. Todd