The first inlay is from USPC, probably the 1930s or so. The second inlay was a Burt reorder

The “M” is clear. What comes after the “M” is the mystery

Could it be an “A”, or “T” or “K”. Or could it be more than one letter
It’s been a mystery to me for 25 years or so. With there being a reorder, the club (or person) was around for a while, so maybe there is a record of the place.