Gotcha. I think I know what you're talking about. My stepdad has a bunch of A5s, and a couple of his very old Belgian light 12's have rounded grips that are halfway between a pistol grip and a straight stock.
Those are Prince of Wales stocks. If you order one. Many fine double guns have them and can be ordered that way. I shoot them better than I do the english stocks. Apparently so did his highness.