I couldn't look through the plug hole on mine but didn't try that hard. Didn't know till I
pulled the head and saw the flat piston. Think if you go out to the Egge website that still sells 273 HP pistons you can see a picture of the regular and high compression pistons. Got a feeling that whoever rebuilt your motor did it right and put the good pistons in it for you. By the way - what's regular gas going for over there a gallon?
Ours is in the $3.8xs now.