I’m confused. I think I’m seeing both a standard trigger and hammer in your pictures. Perhaps it’s just the camera angle and prop rod through the trigger guard obscuring the trigger.

I don’t know how scarce four screw 8 3/8” 17s are, but I’m sure I’ve never seen one. Yours is impressive. As far as shooting it goes, for me the choice would hinge on whether it already has been fired since leaving the factory. If it’s been fired enough to tell, it would take a lot more to make any difference as long as you are careful to only lay it on soft surfaces.