1980 mercury 175 seized?

Just picked up an 78 tahiti with a mercury 175. guy said that it hadnt been started in 2 months or so. had to do some re wiring to start it. got that accomplished and starter engaged into flywheel but did not rotate at all. pulled fly wheel cover and tried rotating by hand and absolutely nothing. in either direction. pulled plugs and tried again and still no movement. pulled head covers and inspected/ sprayed some lube and cylinders look good. nothing looks like it binding or in any terrible shape. let it sit with lube and tried again a couple hours later and still, absolutely nothing. im fairly new to the outboard world as far as mechanics goes, so i need some ideas. theres the obvious, motor is screwed scenario, but could the lower unit cause a motor to lock up? im from the jet and v drive side of things, so any help would be appreciated.

Remove lower unit and try again.------Any water / gear oil in the lower unit ?

had oil and it was clean. no water... checked that before the boat left the guys driveway. ill pull the lower and see if that changes anything