At that price with the extra cylinder, I'd grab it, no questions! They don't make those cylinders anymore.
If the gun has been refurbished at some point, it will probably use .32-20 brass with no modifications. Of the three I own, 2 will take .32-20 brass no problems, both are Refurbs. Only the non refurbed 1935 will not.
HOWEVER. The CURRENT Lee die set WILL load Nagant gas seal ammo. I have such a set, and thats what I use. Grafs and Midway have PRVI Nagant brass, and its really not that hard to load, the bullet just seats deeper in the case than what we're used to. The only caveat is that the gas seal feature works the case mouth pretty hard, and it cracks after 3 or 4 loadings, so I mostly load .32-20 brass conventionaly, and save the Nagant brass for special occasions.
In your case, I'd just use the 32 acp cylinder until I felt comfortable to experiment with the more exotic Nagant rounds. These are simple, robust and strong revolvers. My son enjoys shooting his at our GAF events.