The answer is yes, yes they will.
This is a passenger seat from a '94 (Suburban to be exact) and a passenger seat base from an '89 K5. The seat tracks are also from the K5. The bolt pattern is the same on the '94 seat. The pictures show it not bolted together, but sitting with the bolt holes lined up. The seat is in the rear most seating position.
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*please excuse the mess... still in the never-ending move in process*