For the price of clowns right now I wouldn't work with a het male unless it was a morph, but of course you should do as you please.

I do agree there are some ways you can look at a het clown and recognize it was het clown. I don't think the subtleties are quite enough to be sure of it by the markings, though. The tear drops and funkiness of the pattern look right, but you'll have to wait to prove it out to be sure. Might wind up with a big fat clutch of normal poss hets if you pair him with a het female.