If you have a regular 10/22 and want to switch to the heavy barrel that is on the target model then is the stock all that you need to change as well? Also, will the heavy barrel work with all of the rest of the parts and reciever on a regular 10/22?
Yes all the part and receiver will work with the heavy barrel. You can use your stock but you will need to open up the barrel channel. A piece of sandpaper wrapped around a piece of pipe or dowel rod works well for enlarging the barrel channel.
if you're going to spend the money to put in a quality heavy target barrel, you really might as well upgrade your stock while you're at it. You can open up the barrel channel if you really have the time and inclination - but you'll also need to refinish and seal everywhere you removed material.
I did this same swap to mine about three months ago and it is absolutely awesome... I used a Green Mountain barrels and a Hogue stock and the thing shoots amazing. You will enjoy it.
I have heard of a few people having tight fits between an aftermarket barrel and receiver. Some of the tips I read were to put the barrel in the freezer. It doesn't sound like a common problem but if it is hard to get in you could try it out.