Would an 82-'03 seat fit on an '04-up bike? or is the mounting totally different?

I don't think so. Did you get a new bike? I have bought quite a few seats and I have never seen seats that fit both frame styles.

They changed all the mounting tabs on the 04's and up.

nah, I wound up buying 2 seats to try out, and will be selling one of them. My cousin has an '05, and I'd like to see if it would fit his, If not, then it will either go to classifides here or ebay.