Hey!
Mamma Mia!!! Congratulation on your new "old" Mamiya.

I used to have the RZ Pro II during the late '90s. I sold it in 2000 after I realized the rarely use it at all. Good thing I sold it back than while the price of used film cams was still good.... I didn't loose much at all.
Anyway, the Mamiya 67 systems are well made and a joy to use... beside the weight of course

The one thing that attracted me to the 67 at first was the fact that it is the same ratio as 8X10 of which I like.
Look like yours haven't been use much and still in pristine condition. Anyway, have fun!
Take care
Buddy