Arms do have. If you are talking about those small (usually yellow) hands that can hold stuff, then I can't find any specific markings on my figures hands.
@WESTIEKATH one "fake" out there lacks the little ridges on the hand's pin to better hold inside the arm. I did notice those attached to several definitely-fake LEGO SW torso assemblies I ran into once. I've also never observed a logo on any LEGO hands.
Yeah, checked the arms and on older ones I do not have the Lego logo. But the attachment point to the torso has only one slit. I know that the aftermarket ones have a slit going though the whole attachment pin.
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With hands, the LEGO ones often have quite distinctive moulding marks on the bottom (flat) side when looked at with a glass.
Regarding the hands wrists, then on older ones they seem to be quite square, yes, but on newer ones, they are a bit different. I found this page with a good close up picture:
https://extraextrabricks.com/en_US/p/LEGO-minifigure-hands-yellow-pair/3373