No. The tahoes were redesigned in 2000. They would be GMT800 fenders.
Got your PM and had to do a little looking, but..
GMT400 tahoes were redesigned in 2000 alongside the silverado/sierra redesign in 1999. 2000-2007 would make it GMT800.
The last GMT400 tahoes were built in 2000 as a "Tahoe Limited Edition" but only because they were left over from the manufacturing from 1991-1999. About 8500 were 'released' in 2000. So Technically there is a possibility that they could fit, but it is very unlikely. I'm guessing that you are buying these off of craigslist and there is probably no photo along with them. Try and get a photo of the fenders, if they don't match your's now, then they are from the gmt800 tahoes.