Used GZ came with odd size drum.

[LINY2000]

I have two 2000 GZ 250s. One with no papers so it was to be a parts bike but I think I can get papers and get her running. But looking at the two (and trying to get break shoes) it came to my attention that the drum on the titled bike is larger. This bike also has mags rather than spokes. It's about 1" or 3cm of a difference in diameter. Does anyone have any idea if this is common or if I'm going to end up with some trouble due to a miss matched rim to bike swap?

Thanks for any ideas, I want to get this buttoned up and safe for my g/f to learn on, then to be able to pass it off to a friend, if it where just me on here I'd ride it till the wheels fell off.