Looks like a model #9

Hunter

17j

Does it have a grade # or ?

The 1904 catalog doesn't identify it as a specific grade. Shown is the Model 8 open-faced movement with a similar pattern:

Notice that the cross-hatching in the middle is much more fine in the ad compared to the real thing:

Eric,

Is this called a 3/4 plate movement in Seth Thomas world?

Thanks

You betcha, Jon.

The Model 5 is the only full plate 18-size watch that Seth Thomas made.