Hi dougmac, welcome to the forum. Seems those old Lawn Boys just won't quit. You're right, there will be somebody along who knows Lawn Boys, and I'm guessing Brad will chime in.
That is correctTook a while to get you an answer, but a friend of mine that knows his LB's says:
Tell the other guy with the engine fit question that the Scamp F engine will fit a cast deck, but the muffler plate will not.
The cast deck will swallow the Scamp plate.