They were not stamped there by the mint, but by someone later. If they had meaning to the person who stamped them there - as I suspect they did, since if they were randomly selected letters and numbers they wouldn't be repeated on both sides - I'm afraid you'll have to ask whoever did it, since only they are likely to know.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis