Between my Dad and I, we have a hodge-podge of different barrels, forearms, and frames. We have something to fit everything!
However, if you are just have you drawers in a knot to shoot your new/old 30 Herret, you can shoot it without the forearm. Just be careful not to lose the hinge pin.
I've got a couple of old Contender forearms that I had to sand off a little of the ears to get them not to rub against the "straps" on the side of the G2 frame. I just take a rough piece of sandpaper on a flat surface and take about 1/8" off the ears of the forearm. Then I smooth with some 220, then some 400 grit. After that, rub a little Tru-Oil onto the bare wood and it looks like it came that way!
You may have to modify a forearm to get it to fit, just take your time and will be OK.