To be quite honest, I know little about National machines. For the expert, you need to consult with "Damascus Annie."
This particular machine is like a Singer model 128 (again, to be honest, I don't know Nationals... but if I had to bet, I'd have to go with the Singer as first with this type of machine), but with the very distinctive National-brand characteristics of that cute-as-a-button round cover plate at the top of the pillar (I'll admit it, that's the primary reason I bought this machine... well, that and the pristine decals <g>), and also the peculiar bump in the bed, just right of the needleplate.
The motor is pulley- rather than belt-driven, as is the case with most Nationals. It has a proportionately small handwheel, compared to many other machines of the same vintage... also characteristic of Nationals.
The needleplate is plain...keep in mind, this is how I bought the machine, before any cleanup, after which, I expect, will have this faceplate gleaming.
The serial number on National machines (I'm told by Damascus Annie) is generally below the front throat plate. This one reads 3987T. She tells me that that is a weird serial number, they don't usually have that final letter designation. So it goes...
This machine comes in a domed "bentwood" case:
I have not yet done a thing with it, but will... unless you want to take on the task... in which case, let me know... McKenna