John, that would be a question to post on the "mxtrax" vintage forum.
From a guess .... Honda ? 1987 and maybe a GP setting (or it could be the person assembling it).
Either way, it's worth a shot. Or I could pose the question for you.
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Thanks Ian, if you could please ask the question for me on "mxtrax" I'd be grateful, it would be interesting to find out as I've drawn a blank to date.
From what I know KTM were the first to fit WP USD forks which was around then followed by Cagiva.
Ian, many thanks to you for asking the question; the answers confirm what I thought the markings were for but didn't know for sure, looks like I owe you a few pints for doing this.
Should have them on ebay latter today as I'm having a tidy up and won't be using them.