Finally got ahold of CS and here is what they say I need...
Benelli Part# 60850 available from numerous online retailers including Midwayusa.com(cheapest I've found 27.99+s/h), Brownells, etc. Again, this is if you are converting your Supernova (Non-Comfortech) stock to a Comfortech stock.
This includes a shim kit, drop change plate, and locking plate. The original Tactical steadygrip PG bolt will work (per CS). I just ordered it and it should be here within a week. I'll post the results.