Well I just got off the phone with "Jack First Gunshop" and now have an 645 extractor pin on the way, along with a 6906 grip, 457 grip, and a 2206 barrel nut (restricted part). I paid a little too much for the parts, but I'm tired of waiting.

If I remember the phone conversation:

Pin = $3.00 (6x)
Grip #1 = $20 (about the same)
Grip #2 = $30 (1.5x)
Barrel nut = $4 (about the same)
Shipping = $10