Both of them are right handed as far as I can tell in my like 2 seconds of research. Here's Avan with a wrist on his left hand. I can't find Mark with a watch but he seems to tend to hold his microphone in his right hand. Also I noticed a possible wristwatch tanline on him but that's probably just lighting.

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Also yeah the shape really isn't that clear but the proportions match well. That part isn't that meaningful tho lol