The only time I was downtown(w/the vette), was when I had some rims/tires switched out at NTB. I also drove it down when my dad ran. That's about it. I really don't trust it parked in most areas and especially a valet parking.
That knob does look allot like mine and I been looking online for any extra info and I'm still turning up nothing. I been also reading up installs on the B&M Ripper shifter and their doesn't seem to be any set screw. I might try and call them tomorrow and see if they have any advice. The new knob is a slight variation of the one that I have now. I got it on sale for pretty cheap. I thought it was going to be an easy swap. Look at the pics of the shifter, (not my car), http://www.2phast.com/Corvette/Untitled-318.jpg, I don't want to go about taking it apart, if it's not going to accomplish anything. Let's say it has a jam nut, how would I go about taking it off? Their are no visible ways of getting into the knob from the outside, it's just one solid piece.