Unknown hand etched markings on case? Can you identify?

I found some etchings on my cases when I was replacing the o rings in the pipe. I am curious as to what they are.

They are below the exhaust port on both sides of the case. It appears to say:

52B
2

The 2's could be a Z and the B could be an 8. This is in the same spot on both cases. It appears to be the use of a hand held etcher that makes little dots. The etchings are upside down, about 3 inches below the exhaust port, and on both sides of the case near where cases come together.

Does anyone know what these mean? Are these normal factory markings? The bike is a 2001 YZ250.

I bought the bike from the original owner in early 2003 and it showed very little use. He said he only rode it around 5 times and did not have any engine work. I believed him as the side cases showed almost no wear of the paint, original plastics in excellent condition, etc.

Since they are the same mark and in the same place on each case, could they be markings to identify each side of the case as a pair? If so, for what reason???

Thanks for any input as I am really curious as to what this is.

I have photos of the etchings but the spam filter does not allow the link. Is there a way to attach the photo directly or any other method?

Thanks for the replies.

I found out from a mechanic that the factory actually made the marks. I looked at my 03 YZ250 and it has it as well.