Thanks everyone! Macybaby, if you had/have one with the same decals that confirms it for me. My only hesitation was because of the VS/front tension/bed mounted stitch length combination, but I couldn't think of any better match.
NZQuilter, it is in really good condition - it's clearly been valued all its life, and not left outside or in a damp basement or anything. The current owner never sewed on it - she used it to display handmade dolls. I very rarely see cabinets that look this nice around here.
JoeJr, the shuttle and one bobbin are there. Looking closer I don't think all the attachments are for this machine (it has top clamp feet, and some of the attachments are side clamp), but there is at least one hemmer that looks right. I've been looking for a treadle that doesn't need a lot of wood restoration for about 6 years, so I'm willing to be patient looking for accessories.
The only problem Mom noted is that the screw to hold the needle in place is missing, and the needle is bent and jammed in place. I had asked her to bring a needle to compare length, but she wasn't able to get the existing one out of the machine. This seems fixable, though.
Now to see if the seller will hold it for me until Labour Day...