I have the same model. The rear lens, I found out much later, suffered from severe fungus. But it could be repaired (and recoated) and it now is my beloved take-anywhere camera. I even sold my 2.8F planar, since I decided I could get more for that model while the results of my 2.8C Xenotar where no less spectacular. The repair did add to the costs, but the camera still is the one to go for me (I have a Rolleiflex 6008i and Pentax 645N as well, and just sold my Plaubel Makina 67).
CLA is worth it. I am probably replacing the screen with a Mamiya 67 screen too (not the more expensive options of Maxwell etc, not because they are too expensive, but because they may be too bright in daylight).