If we could see the shuttle and length of needle, it might be easier to tell who made it (especially if it is White). I spent some time looking at pictures, and didn't see any Howe with that style of slide plate configuration. Does not mean it's not there -just not on Needlebar. They have a lot, but they don't have everything.
I'm trying to figure this out, because if it isn't a White, it might be one of the few I'm still looking for- but I'm not 100% sure what they look like LOL!!
it would be on my way to Madison. . .