i'm not sure what i'm looking at. is the grey part just dirty or is the finish worn away? the bottom line is this: do you want it $300.00 worth? or do you want one to keep up with someone else? or for an investment?
if you know for a fact that it works well and you love it and always will, then make an offer. remember, she'll try to raise the offer, so offer a little less than your end price.
if it's an investment, it's too iffy, imo. there are too many of them and antiques as an investment are very trendy. right now people are more into traditional, for example.
if you're thinking of using it, i have one complete cabinet and machine, never electrified, that i love, and three wrought-iron bases that i use as table bases because i can't GIVE them away. my daughter, who's 5'7" can't get her legs and foot pedal under the things. neither my DIL nor my DD wants to sit and treadle after coming home from a full day at work.
if you're getting swept away because so many members have them, then you have to think about whether that's a good reason.