William,
I used some Polyuretane (Minwax) on my antlers 3 years ago and they still look exactly like the day I did them, absolutely no color change at all. This is the only pic of the rack that I have right now, will try and get some better pics tonight if I think about it. The was my largest rack to date till I killed the mule deer and I was comparing the two racks. Anyhow, the smaller rack (the whitetail) has had the poly on it for 3 years now...