I have a left side 4iiis power meter on a 105 crank arm. My bike came with 105 parts and now I have an extra crank arm.
If it fit on a bike with Claris parts I would put it on the bike. It might look strange but I don't care. I'd put it on a bike with Ultegra parts. I'll hope to put it in my next bike if it still works.
And, yes, I'd take a Yaris to the dyno if the engine were my legs.