Odd foresight blade for No.4 LE

[lawrence_n]

I have a Long Branch marked foresight blade about which I have few questions. From what a fairly knowledgeable buddy told me, the blades are marked in height increments with plus or minus stamps. This one has him stumped. Mind you, it's in an English foresight base so not really the proper blade for it and the stamps can be read either way so it's either "60X" or "X09", but I think the former is correct. It's a pretty high base from what I've seen.