It is not a problem if you have wood stocks on it.
Take the forearm off the gun and remove the 2 screws that hold the plastic spacer on.
Take the spacer off of the forearm.
Now get some tape, paper, cereal box cardboard, etc.
You are going to make a shim between the plastic spacer and the forearm.
Now lay the plastic spacer (flat side down) on whichever material you have chosen for your shim.
Trace around the edges of the spacer making an outline onto the shim material.
Follow the lines and cut out your shim. (make sure you cut out for the screw holes too)
Place the shim in between the plastic spacer and the forearm and put the screws back into it.
Place the forearm back onto the gun and see if it is tight now when you open it.
If it is still a little loose when you open it, you need a slightly thicker shim.
If it is a little tight when you open it, you need a slightly thinner shim.
Adjust the thickness of your shim until the gun is nice and tight when you open it.
Remember...
You can use anything as a shim... all you are doing is taking up a very small gap to tighten things up.
Paper, tape, cereal box, furnace tape, etc.
Don't be surprised if it only takes the thickness of a piece of paper to fix things.
Spanky