Wow, impressive progress, you are really blasting through this thing. What made you take the trans off, was the clutch slipping or any other symptoms? Or just to check it out?
I've reused the throwout bearings before -- with success -- though with the amount of wear on the fingers of your diaphragm I wonder if yours may not be 100%. Generally Volvos seem to come with terrific bearings everywhere and bearing failures are pretty unusual. I've got a hunch that this might be because Volvo's car business originally began life as a division of the SKF bearing company -- maybe some of that still runs in the company's blood. Generously-sized, well-designed bearings seem to be the norm -- many of them still supplied by SKF as the OEM.
Watch out on the pilot bearings though -- those are a spot for caution on these because the OEM bearing is NLA from Volvo, and all the aftermarket bearings, the Kolb one included, are a different design with a crappy plastic needle cage and no grease seal (aka junk!). The OEM bearing is made by INA. Even the OEM one isn't the most robust -- perhaps because it's the only bearing on the car that was specced not by Volvo itself, but by VAG.... My hunch anyway. (Compare the little open needle pilot bearing for a D24/T to the large, sealed ball bearing used in a redblock gasser Volvo and you'll see the difference!)
See pictures for comparison:
OEM INA w/ grease seal:
Aftermarket Kolb without seal:
Don't put the crappy kind in, you will regret it! Volvo's decision to discontinue selling the OE bearing is unfortunate... I'm working on a guy's 745 now that had the pilot bearing implode and needs a new one, so I got to work last week on finding a way to get the good bearings. Fortunately I was lucky to get in touch with a source that has access to 19 of them, at $10 apiece plus shipping, I have to order at least 2. They won't come in a Volvo box, but they're the same INA part that Volvo sells in its own package.
Edit - INA number is F-85706, same as your National number, maybe the National product is a reboxed INA too?
I'll be putting together a group order for these, in case anyone else here wants one -- I'll start a thread in the Powertrain section about it shortly, hoping to put in the order this week.