I would say that is a great price if the camera is functional.
Light leaks and accurate shutter speeds are your biggest concerns. Both can easily be repaired though so even if things end up not being perfect you can get the camera fixed or just replace the individual piece that isn't working. That is one of the great things about modular camera designs. When one part fails the camera isn't a total loss. I would also bring a roll of film with me and run it through the back just to make sure it advances smoothly and doesn't seem to "slip" which would result in overlapping film frames.
Any obvious light leaks can be inspected with a flash light and a dim room. I once met up with someone on craigslist to buy an old folder and I ended up taking the camera into the coffee shop restroom, turned out the lights, and inspected the bellows with a key chain flash light.
Overall the RB67 is one of the most reliable camera systems ever made. If this camera was owned by someone who just used it as a hobby camera it probably has a lot of life left in it.