Hi Woof*,
I'm not having trouble with the insert, I'm having trouble with bezel ring that the insert snaps into. The TC bezel snaps on the crystal retainer just fine, but the gen is just a little smaller than the TC. Here's a link to a bezel from wholesale outlet on ebay:
http://www.ebay.com/itm/BEZEL-INSERT-S-STEEL-FOR-ROLEX-SUBMARINER-16610-PART-/310304838667?pt=LH_DefaultDomain_0&hash=item483f9c140b#ht_4842wt_1270
I wasn't sure if I had to buy one of these too, or if it would even fit a gen bezel?
http://www.ebay.com/itm/RETAINING-BEZEL-INSERT-FOR-ROLEX-SUBMARINER-16610-16800-/310304841634?pt=LH_DefaultDomain_0&hash=item483f9c1fa2#ht_4918wt_1270
Thanks, Bob.