Pretty sure that Dan is correct, about the Mathis profile Stuka.
I know RSM has kitted the Don Still designed "Stuka Stunter" for a long time, and recently saw that Brodak also kits the Don Still "Stuka Stunter". While there were various developments by Don, plus the Ambroid kit version, both the current kits claim to be OTS legal. I noticed that the RSM kit is listed as 479 sq. inches, but the Brodak kit only 391 sq. in. They may not understand that the flaps and wing both count in the wing area? Spans are listed as the same, 47 1/4".
There is also some duplicating of efforts with the 1959/1960 Thunderbirds, and while both have Hawker Hurricane stunter kits, RSM's is Jack Sheeks' while Brodak's is Palmer's. Puzzling enough?

Steve
builtrightflyright@builtrightflyright.com is the email address, and it says he'll check it when he can.