Thompson is comeing out with the new G2 frame to replace the Contender.I was wondering if the old Contender Buttstocks and forearms will fit on the new G2 frame.I have read the old barrels will fit but have not seen anything about the stocks.

Last I heard, the grips and buttstocks will not fit the new G2. I don't know about the forends. The G2 buttstocks look like the ones on the encore.

Old and new forends interchange, Not so for the Buttstocks (New Grip angle).

Contender G2 stocks

This is from the T/C website

G2 Contender Compatibility with Old-Style Contenders: The G2 Contender frame will accept all Contender barrels and their corresponding forends (except Herrett forend). The G2 frame will not accept old-style grips because of the change in grip angle. Blued or stainless barrels are readily interchangeable.