have the cross slots on the receiver. The mounts have an integrated, hardened, horizontal cross pin that "marries" into the slots on top of your gun.
EAW no longer makes these mounts. You can find them used but the last one piece EAW made with these hardened horizontal cross pins for the Feinwerbau and old Webleys that I've seen sold on ebay for over $300.00 about a month ago.
Another option is to find a scope stop pin that has the hardened horizontal cross pin (not vertical pin) and use any mounts you want. The last one of these I saw sell on ebay was a week or so ago and it went for $48.00 plus shipping.
Probably your quickest and easiest solution is to buy a new set of sportsmatch mounts for the FWB. To my knowledge sportsmatch only makes these for a one inch scope tube and they only come in medium height. You do have a choice of one piece or two piece mounts though. I prefer the flexibility of a two piece mount. The one piece medium height, single screw, is part no. OP22. The two piece, medium height, double screw is part no. TO3C. Please note the two piece part number on the package is TO3C but listed on the website as part no. TO3S. I think the info on the website is incorrect but I would check with Michael before placing an order.