Beautiful car - I've always loved that 944. Well, I love the "S3" even more apparently.
Treat that top like gold - the bows are NLA as indicated. There's a manual for the top, it's called the "944 S2 Sealing Body Cabriolet" manual, and copies are available online.
The two pivot bolts are not removed, they're just backed off a few turns - it's the very first thing I did to my roof, even though it was working perfectly. They're located behind the little round plugs on the sidewalls in the back seat area.
Treat all of the rubber seals with pure silicone grease, wiped on with a finger in a thin coat. If your top pins (one on each front corner) or their mating points are worn, you can put shrink tubing over them to quiet the rattling, and/or I found that a very thin (about 3/8") half-round piece of soft silicone body sealer, caulked into the very front of the rail at the leading edge of the roof, provides just a little bit of "spring" against the roof, and is just sticky enough to make the top completely quiet. No more rattles or squeaks.
I put a whole new top on mine a couple years ago, even though the original looked great. Once it was removed, you could actually tear the fabric with your hands it was so worn out. If the stitching is faded white, it's a good sign it's time...
Try to get the "boot" cover for the top - you don't want to drive around for long without it, because dirt and stuff will get down into the car body and the mechanism. They're available on eBay, and those fasteners are called "Tenax" fasteners if you need to find them. I didn't see it in the picture.
Good luck with your car!