Frame number confusion

I recently bought a 1936 Norton ES2 in need of a complete restoration. According to the origional service book, and the later log book from 1961 the engine number is 70372, and the frame number is 70435. But the actual number on the frame is 70372, and what I beleive (though not certain) is the origional engine, has a different number againThe origional service book has these numbers handwritten, so one theory I have is that these have been written incorrectly from day one, and just copied accross still incorrect to the log book issued in 1961. I've stripped down the frame ready to paint, and not found any other markings that look like frame numbers (though there are a couple of what I think are part numbers in different places)I've not found the number 70435 anywhere on the frame nor engine.Is anyone able to look up the numbers I've mentioned to find out more and give me some clarity?Any help would be appreciated.ThanksAttachments IMG_20131019_162115.jpg