Hub bearing Problems

I have a 98 bravada and I ordered a hub off of ebay. the part number they sent to me is 15731627 ac delco #fw155. When I went to take the old one off I noticed the new one has no splines on the inside of it like the one i am replacing. Just wondering if anyone new the correct number that i need the ac delco site isn't working. thanks

The BCA # is 513124. Advance Auto online will ship free. $175.00 to your door. I replaced both of them over 100,000 miles ago and they're still as quiet as the day I replaced them.