Here'* my old 1998 SSE in Firemist Gold. It was a 1998 only color I believe, but there is a gold on 2000 SSEi'* that looks to be identical, yet I don't know the RPO code for that color.
Pop your trunk and roll the carpet off the plastic spare tire cover. There is a sticker with a lot of 3 and 4 letter codes. On the bottom line you should find the RPO code U 370E
Also, here'* a link to an old post of mine concerning it -alot of pictures are not available any more, but there are a few I made comparing the darker Firemist Gold to the champagne color also available in 1998 (actually 1996-1999).