this is coming from the datsun 620 (truck) community, where just about every single 620 owner has their carrier bearing BUSHING/INSULATOR (not the actual bearing itself.) is deteriorated/non existant.
what that will do is allow the driveshafts to clank around inside the insulator housing, but it will smooth out once you get going/up to a certain rpm. this is bad because it will put undue stress/wear on your u-joints, and youll have to replace them sooner.
HOWEVER! your insulator is still
there which is whats important. it has a little play, and i dont know what the high tolerance for play is but i would say its good and nothing to worry about.
also, next time try to have the camera more steady so we can actually see how much it is moving
