May have been a factory upgrade/conversion.
Just to be sure: Is it the numbers for the flash delay, on the top deck around the shutter speed dial, that are red?
Check this link, point #8. http://www.peeble.com/screwmount.htm
“Believe nothing, no matter where you read it or who has said it, not even if I have said it, unless it agrees with your own reason and your own common sense.” – quote
I myself am made entirely of faults, stitched together with good intentions. -quote