I don't see it as a valuable part for which you're going to get $100. I see it as a part that you would put on eBay and it would languish there until one of the other Rockets owners who'd had his shifter castrated decided to spring for an original replacement. And then, if he were typical of Rocket owners, he'd want to get it for $19.95 unless you embossed "140 cubic inches" on the side.
FWIW, if you get gout in that big toe on your left foot, you will be very glad to have that heel shifter. It may be the difference between being able to shift and not being able to shift.