Thank you for your note. I actually noticed that the black rubber piece fits in the stock in the area you suggested this morning—but when it is in place, I cannot reassemble the gun. There isn't really a space to fill between the trigger guard and the stock (unless I have it in backwards or something). Basically, without this piece the stock seems to be flush against the guard. I am wondering if it is a necessary filler for some shotguns (M2, SBE, etc) but not the SuperNova.
David