I say you are right the way you said .
Looks like the valves are off sett so the head / valves should match the piston cut outs .
Sit the piston on the head and line up the cut outs to the valves this will tell you which way .
It's not a dumb question better safe than sorry
Some Pistons have arows showing which way they go , going off manuals .
The cam will tell you to the biggest lobe on the cam should match the biggest cut out on the piston .