Thanks very much chaps.
And guess what ?
I've found a photocopy of the 'missing' notes !
I haven't found the complete file yet, although I think it's under a couple of heavy boxes, where I've been moving stuff around. But the main thing is, I've now confirmed the presentation style of the serial numbers. Aircraft built at Inglewood had a 'normal' serial style, example FL123, and those built at the Kansas City plant had the hyphen between letters and numbers, example FW-192.
So that's one niggling thing off my mind, and I can stop looking under rugs, on top of wardrobes and in the freezer !!