This is the one with the wide throat plate and knob tension. I'd lean towards this one being made by National also, looking at the underside and what shuttle it take would help.
http://www.ebay.com/itm/Antique-Bart...3D221554849580
And this has the top leaf tension and the narrower throat plate (this one I'm sure in teh National Seamstress model, I own one like it).
http://www.ebay.com/itm/Antique-Bart...item51a8b647da