the metal disk is actiually just a sort of sticker... I have 2 types of peregrine seat, the one you describe is the Elina one but I also have one that i got from a factory peregrine expert and its based on a dominator seat but is stamped peregrine on the sides, I have only ever seen 2 of the dominator type so I guess they're bloody rare, the elina one is obviously more common.... there is another peregrine seat which you can see on US ebay, i think they came out a lot later maybe just before Peregrine ceased