I had a circle-stamp KC Firefird that came out right before the first DX Valk made it's debut. The first run of those had what was called "wet plastic", and they were understable fast super-long-distance flyers. Nothing like a DX Firebird at all. I got my first 400+ foot birdie with a putt with that disc. The problem was that they were "one tree rollers".
But man they flew understable sweet.
I remember those KC Firebirds, they were absolutely nothing
like other Firebirds. They flew really far, indeed! But boy did they beat up quickly; I went through them like water.