Biohazard

Referencing the pic below, I'd like to pose a question.

My Victor Reinz gasket kit has 2 kinds of valve stem seals; 8 short and 8 that are a bit taller. The seals I removed from the engine were all identical (and hard as a rock). Which is correct? Could someone have replaced the seals somewhere along the line and installed the wrong type of seal on half the valves? Not to mention, the new seals don't match any of the ones I pulled out.

The seal on the far right was removed from the engine.