EXCLUSIVE

Great news for rich UFC fans -- the iconic "superfight" belt from UFC 5 is about to hit the auction block ... and you can add it to your mantel if you're willing to drop a small fortune!

Backstory -- UFC legends Royce Gracie and Ken Shamrock threw down to crown the company's first ever superfight champ back in '95 ... but their 36-MINUTE bout was declared a draw, so neither of 'em took home the gold.

Now, Goldin Auctions -- consigning the strap for a collector who got it from UFC co-founder Art Davie -- is bringing it to a bid ... and expects it to go for $25k-$100k (if not more).