Maybe. In the early 80's or so, Silverton's Mainship model line included a 40. Might have been two kinds, on e sedan (or convertible or whatever) and one maybe an aft-cabin. This woud have been contemporary with their 34, which was single diesel and a semi-displacement hull with a full keel. Not sure what the 40s hulls were like, but I think they were all twin engines of some sort, often (maybe almost always?) gas.
Then Mainship turned into its own company (still under the Luhrs umbrella) and moved toward another market, planing boats, but also introducing a usefull access to the bow using steps down from the middle of the flybridge. (Silverton put those same kind of steps on the sides, or on one side.) Don't know much about that era.
Then in the early 2000's (or so) they introduced the more of a trawler-like 400, after the 350/390 and the 430.
Much of this is from memory, and mine's usually faulty... but it might pay to check years of production when you're comparing.
South River, Chesapeake Bay