Remember that old saying "Yes Jane...There's a difference". To convert a Mk1 to a Mk2 you need to remove the rear tie plate and pin, cut the web, inlet for the trigger hanger, patch where the tie plate was removed and drill/counter sink for the new tie bolt. Then there's the front receiver reinforcement to deal with. It's work and can be done. It's far easier to sell your MK1 stock and buy a Mk2 stock. I've got a few Mk2 stocks...if interested PM. Ron