Surely it wouldn't cost $220 to dremel it?

You could have used a diamond point pen (not expensive, from an art shop); you could have asked your friendly local dentist to help...
I've had a bit of glass someboody marked with their own name and address, just scratched with (probably) a diamond point pen.
I do agree the repros should be marked as such, so they can't be passed off as the far more expensive originals.