Hi Monty
There is a way of removing glued plastic from a gun stock, put the stock in a polythene bag and put it in the freezer for a couple of days. The cold causes the plastic to shrink and break the glue bond if an epoxy resin glue has been used to fix it to the wood, also taking it out of the freezer and working quickly give the plastic a good sharp tap with a hammer in the centre very often shatters the plastic.
I have used this method myself and it works fine with no damage to the wood.

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