X2 you two. Just make sure both studs about same height, you don't want one not screwed into the aluminum enough. I don't car how they come apart, not a problem. Correct way would be breaking nuts loose and re-installing stud alone first.
The middle pic given there is the crap tensioner and sailor killed one just as mine did, the anti-friction insert is paper thin and crap. Once it wears through or tucks under to wad up things start sticking quick. Thinking the plastic used there not the best either, it gives in to wear and distortion like lightning, there are much tougher soft plastics out there.
Gates is full of crap, a spring is a spring as long as tension high enough, the flat one is actually quite a bit more robust than the Gates springs I've seen, I like the stronger ones better. They do not bounce erratically nearly so much and that stops most noise and possibly breaking the tensioner arm in half from impacting. Lighter weight springs sometimes produce a knock on engine startup that will have you thinking dry start rod knock quick. Have someone crank car while you have a flashlight trained on tensioner and watch it go apesh-t at start, it knocks. Stronger tensioner spring stops that instantly. I have rebuilt the top Hayden/Dayco tensioner, flat spring but stout and works good BUT some come with a stupid teflon tape insert that runs between the spring rounds to prevent coil to coil abrasion, it wads up quick to DNF the part in maybe a month or two. I remove that tape and seal up the unit OD best I can with foam tape after lubing inside generously with powdered graphite, it runs forever. The front aluminum swedge is easily ground off to allow the front plate to come off and the center hole easily drilled through for a throughbolt with self locking nut on back, a couple of spacing washers and back to a viable running part. I handtest all tensioners at the parts store, I don't want it unless it takes close to everything I've got to budge the arm off its' stop, on some parts that can be moved fairly easily, not enough spring there, will cause trouble. I have one of the new Gates redesigned parts like the bottom pic, the longer center post will stabilize it better. Grind that rivet head off and drill and tap the end of shaft for hardened 1/4"-28 bolt and washers to shim tight and that one rebuilt too. Got one done like that and already running. $50+ part for say $2 and twenty minutes work again.