This is an interesting question. Engine numbers and frame numbers don't match. Frame is the VIN of course, with model and year ID, and that's what counts. Engine number (my best guess) reflects a series, or year range for parts reference. I wouldn't know how else to match a motor number to a particular frame. When doing the recall search at Piaggio, the engine number is not given. http://static.piaggio.com/recall/form-piaggio_en.html
However, of my 2 bikes, the '02 has KR in the vin giving the model, "Sport" I would imagine. The recall inquiry reveals "Tenni", The motor number on the bike starts with KR. My '03 Rosso Corsa has a KT in the vin indicating Rosso C, as does the Piaggio site. The motor number also starts with KR which could mean one of two things. The motor has been replaced (no indication of that) or like many '03 bikes, it was just an '02 carry over. The sequence difference of the 2 motors is 9644, which seems rather high.