Talkin' in shades of grey man! It all depends. As far as US copyright laws go, you can copy anything you want for yourself, you just can't sell it.
My father owned a 20ft POS "Cruisecraft" in the 70's . Boat was a dead ringer for a Wellcraft V20 steplift. But ChrisCraft sued 'em instead because of the name. So they changed it to "Cruise Boats" but still went out of buisness. Word was, it was a couple of Cuban's in Miami or something makin' plugs.
Shamrock just went out of buisness and the molds were an asset of the corporation. The receiver was trying to peddle them on the Shammie site. Sounded like the good one's were long gone. But by buying, you would still get the rights.
Midland's were made in Coventry, RI. It probably would not be too hard to find out what happened to the corporation. If they went into receivership vs. bankruptcy, then they probably just went away and nobody got hurt. Remember, they were a small company and maybe they may have been bought out by someone else but I don't think so.
BTW....That 1975 Cruisecraft is still around. A guy down the street from me has it now. My Dad was the original owner and he lives 20 miles away.
http://boat-manufacturers.findthebest.c ... Midland-Co