I have the Nak MC-500. Bought it NOS about 17 years ago. I only played it to confirm it worked, about 5 minutes. Tried it again only last month, thinking of selling it. This time I listened for 2 hours, and thought "No, it's too good, I'll keep it." At some point, when my current arsenal is worn out, it'll become my main cart, and I'll be smiling. With only 2 hours total playing time, it's not even close to broken in: yours is. And I detected no problems with the suspension, so yours is likely good too — can't speak to the condition of your stylus.
Warmer than most MCs, and very musical. Mine lacks a bit of detail compared to my "higher end" carts, but the stylus is 0.3 X 0.7 so the micro-details should come with break in. It's output of 0.9mV is kinda betweenish — probably OK into your MM input, but may need a boost, depending on your preamp's gain. It's a little hard to mount because the lugs are quite shallow and the screws slip out, but just hold them in place with your fingertip while tightening.
I can confirm, in one man's opinion, you have a very good cartridge to go with that sweet TT.