That's a new one to me.I had 2 CR125's back in the day,and they both had 6 speed gearboxes.I know at some point/year they changed to a five speed...late 90s or so....but I'm not sure if Honda kept the 5 speed through-out the rest of it's exsistance,or went back to the 6 speed..
...I never heard of a CR125 that had a 7 speed gearbox....but maybe I'm wrong
*Edit*....See if the guy will let you take it for a rip before buying it...then you'll/we'll know if it really does.