Is it me, or does it look like the ribs don't taper (in the middle picture). Though they do appear, in the third picture, to maybe have a slight chamfer. Hand caned seats too, eh?
I may be mistaken, but it's my understanding Thompsons weren't very often given a serial number, or if they had one, the system is yet to be officially determined. I'm sure Dave or Andreas will be able to provide much more expertise...
The boat looks in ok shape though - maybe see a couple of spots where I'd check the planking. Probably paddleable depending on the canvas, right? Re-canvassing is easier than you'd be led to believe (take it from a novice).
I'll let the real experts chime in. Welcome to the forums, incidentally, and the wonderful habit of canoe collecting.