DDR 6x2 bayonets serial markings

[rogueX18]

Greetings!

I wanted to ask the "hive mind" here about the electropenciled serial numbers on the DDR 6x2 bayonets
Did they always have a letter prefix or not?
One example:

Ser. number: 17996

However, one on the "Bayonets of the World" website:

Ser. number: Y 7451

Also is the top one maybe a fake or repro? Look alright to me.

Thanks in advance.

[AndyB]

Possible there is I 7996 in real?

[rogueX18]

Yes, I thought it may be an I instead of a 1. Not sure really because I can not get a better photo.