TKO 600 Shifter Question

[67FBSCODE]

I'm new to the newer style trannys. I'm installing a TKO 600 in my 67. I read a lot of post on the T5 and Tremec tranny shifters and decided to get an aftermarket shifter. I was having trouble finding one listed for the 600. I called my tranny supplier and he said they do not make one for the 600 at this time. He said the 600 has a better shifter then its predecessors and that it was a billet shifter. The problem is that after I install the tranny I will have to remove it to change shifters. I was wanting a Pro 5.0 and thought that the 3550 shifter would work, he says no. Is he correct? Thanks John