UPS damaged a sleeve on a cylinder that I got a while back and I just replaced it. I got another sleeve, heated up the block, pulled the old one out and put the new one in. Make sure that the sleeve is pressed in all the way. If you are getting it machined, you should have them press the sleeve the rest of the way in after you put it in, then deck it. Decking is just reassurance that it's flat. You have to make sure the sleeve is in all the way after you let the block cool down because as the block cools, the sleeve will rise up off the top shoulder where it sits in. You can bolt a plate on top of the cylinder while it's hot to keep it down, but a machine shop shouldnt have any problem making sure it's pressed in. It's not a lot of work and if you want the assurance that you wont have a problem down the road, go for it.