I'm not versed in all things "treadle", so don't know what models are going for. I also don't know anything about the Franklin brand.
I do have several vintage sewing machines. Based on what I see, I think it's a pretty good deal, if you are buying it for your own use. The machine appears to be in great shape, with the decals intact. The cabinet doesn't appear to need refinishing, either.
Like most vintage machines, I don't think you can resell it and make a profit. Maybe some of the die-hard treadle people can advise you on the brand and what to look for. If you do not get a satisfactory answer here, go over to
http://Victoriansweatshop.com. That's where many of the die hard treadle people are.
bkay