Pay attention 18! The OP was looking for a "no rail" 4513TSW like your Unicorn! He got a tip, looked quick and in his excitement, he thought that pre-rail 4513TSW in the Classifieds was a "no rail" 7-rounder just like yours! So he snapped it right up!

Then he realized his "opps"!

Such is life. I've gotten excited over a few "finds" myself, only to figure out that they weren't really what I had hoped they were... so I get it. Excitement happens.