Mark, you're throwing too many unrelated 2.3L's to the mix... there's that many different intake port setups just for the 2.3L Lima engine alone... There's Oval, D and the dual plug just on the Lima 2.3/2.5. The exhaust ports are the same on all Lima engines.
First off, the gasket sets don't really match the ports, the gasket ports are almost always about 1/4" bigger than the head or the intake on the gaskets I've used, check that the bolt pattern for the intake matches the pattern on the head and the intake manifold, that is going to be your main telltale as the bolt pattern on the different intake patterns are all different. Also, the gasket ports tend to be slightly differently shaped than the head or the intake.
If the gasket doesn't match the head or matches one and not the other, you have a wrong part, if there's no spark plug holes that's a dead giveaway as a '91 will have 8 spark plugs... If the original didn't have 8 spark plugs then someone has been into that thing before...