I believe you have the black rims that were only available on the 1992 SSE and SSEi models. These rims were powder coated at the factory to match the color of your paint. They are not hub caps but actual rims. You do have a center cap (like a small hub cap), but changing that to a different color would not look that great as the majority of your rims would still be black. If you are looking for a different rim, there are many rim manufacturers out there. Look on the web or visit Canadian Tire (I assume that they are like most tire companies in the US that offer rims as well). They will probably have some on display in their store (but I don't live in Canada and have never been to a Canadian Tire store), and should also have several catalogues. If you are looking for something different yet still OME, try the salvage yard for some rims off of a wrecked Bonnie. That will be the least expensive alternative.
However, I must stress that the 1992 SSE and SSEi were the only bonnevilles of that body style to receive the body colored rims. They did offer them in 88-91, but that was a slightly different body style. In 1993 they no longer offered them. You have a true classic as not all SSE and SSEi'* received these rims in 1992.
BTW, any Bonneville rim from 1992-2003 should fit as they have a 115mm X 5 bolt pattern. I am not sure about the earlier Bonnevilles, but I think they may have had that bolt pattern too.
Retired Moderator, The Bonneville Club www.bonnevilleclub.com
RIP Oldsmobile, April 29
1995 Bonneville SE Supercharged (Stock)
Current Mods: Dirty GYM Sock air freshener.