Yes I think that's the most likely full year it could be. I'm not sure exactly when they changed the soundbox, but I've read they transitioned from the front winder at some point in the first year (1926) and went to pot metal at some point in 1928 so it could be late 26 or early 28 too I guess! But for simplicity I think calling it a 1927 101 is about right as I'll never know for sure with it having no serial number!
Does anyone know when they started serial numbers? It predates that.
Now the second machine that arrived today also has the same brass soundbox, but is just new enough to have the data plate too with a very low serial number! No. 5038. Also has the newer style carry strap (like a 102) and a weird "pinch to open" lock I've not seen before. Again its a 410 motor.