Picked up a 98 Park Ave ultra as a project. Previous owner was told it needed head gaskets. Of course it was LIM gaskets. Its all back together and runs good. Problem I have is about 10 secs after start up volt light comes on and stays on. Alternator puts out 14.6 @ idle with no load. The electronic display says 13.3ish, for what that'* worth.
Got to looking @ alternators and the one in my car isn't a 98 according to any pics I see they all appear to bolt in from front. It bolts in like the 99 & up ones front right bolts in from the front, the 2 left ones are vertically mounted.
Any chance this is the reason the volt light comes on ?
With the plug unplugged no light. Since it charges and has the light plugged in is it safe to assume the wiring is ok ?
Any ideas would be appreciated and please forgive my ignorance on this matter.

You're talking about the way the alternator bolts into place?

Any chance this has had the engine swapped out?

Yes the way the alternator bolts on. No idea if it was a swap.

You need the proper alternator.

When you tested the voltage output of the alternator, were you testing at the battery?

Tested @ the battery and the alternator

Maybe some pictures would help us here.