You can open up the camera, put the lens in B mode, and fire the lens with something like a piece of ground glass over the film area to check for vignetting.
If in need of hoods, let me suggest the rb hoods, which are very inexpensive and fit standard filter threads. The 50/65 hood would seem best suited to wide work with a mamiya 7- as a travel feature, it kinda folds back a bit so you can use that in case you see some vignetting. I don't think the 50/65 hood will vignette though, it has something like a 77mm thread attachment circle, or maybe a bit larger. I can check if people are interested.