I don't know anything about that particular machine, but it looks in good (clean) condition, as does the table. The ad say's it's all metal parts ... hopefully that includes the gears. The price is certainly right!
Take some fabric pieces and thread with you, ask her if she has a needle, if not get the needle size and bring one. Test the machine out - straight stitch, reverse, and zig-zag. If it sews correctly, I'd get it.