GEO Storm 1.6L SOHC -- More than 1 design?

I own a 1991 GEO Storm 1.6L SOHC V.I.N. "6" Engine Code 012075

I recently bought a short block advertized as a GEO STORM 1.6L SOHC.
My Mechanic just called and said that my original HEADS, Oil Pump, etc. do NOT MATCH nor FIT this new short block!!! My original engine has been pulled and disassembled already.
My question is this: IS THERE MORE THAN ONE TYPE OF GEO STORM ENGINES THAT ARE 1.6L SOHC????????

There's the 1.8l but I have no clue if parts are swappable cause it's a dohc