Timing set woes

Safe to use? Yes. Not a ton of slop there so maybe a couple of degrees of cam variation; put the damper on and see how much you can turn the crank back and forth 'til the slop is taken up one way and then the other. Then check to see how much the movement on the damper mark equates to degrees on the timing cover marks. If this was a low performance engine, I would use it.

And if the block mains were align honed, then any chain will have a bit of slop in it.