You need to find out if it's an 8.2" 10-bolt or an 8.5" 10-bolt. Once you do that, you need to use a carrier that is compatible with the gears you intend to use. Here's a site with some pictures of various GM rear ends:
The 8.5" with 3.73 gears should have a "3-series" carrier, used with 2.73-up (numerically higher) gear ratios. It should have "410408N" cast into it. It will NOT work in an 8.2" rear end. Any 8.5" gears that are less than 2.73 will use a "2-series" carrier, cast 410409N.