What Shifter/Tranny Do I Have? STIFF SPRINGS!

Hello,
I just bought a new toy and was told it was upgraded with a TKO 5-speed. I've since dug in and it looks like it was a Keisler Perfect Fit TKO. I'm not sure if it's a 500 or 600. Any sure fire way to tell?

Also, the shifter is ridiculously stiff from side to side, my wife can't even move the shifter. Any thoughts here? I'm thinking maybe it's the spring(s)? I've done digging but can't find anything as it's not your average shifter (In pics). It's the Blue one built by Keisler and isn't your standard Red Tremec shifter, which you can open up the sides and pull out the springs. Anyone ever deal with one of these before?

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