So I have the opportunity to pick up a mamiya rb67 pro-s with WLF, 127mm and 180mm kl lenses, and 3 backs. All in great condition for $300. I've been looking at these for a while but haven't really had a need for one yet. But I feel like this is a great deal that might come around again later if I do decide to get one. I already have a M645 pro as my everyday shooter. Is this a smashing deal and I'd be stupid not to buy it? Thoughts?