I have the identical engine, stamped 146F. I'm missing most of the engine though unfortunately. Definitely a Schoenner. Falk always had JF on the engine. F stamp is typically Schoenner. Thats a beautiful engine!!
Good photos are probably more important than a brand name on a listing, avoid busy backgrounds, capture all the different angles, etc.
Typically, Falk has a JF. Schoenner only had the F stamped on bottom of base. My Schoenner is 146F and is very close to yours.