Martin guitars are probably the most copied guitar ever. I bought a D18 back in the 70s but I’ve not taken it out of it’s case in months. In fact, my main go-to guitar is a “Martin Copy” - a Santa Cruz Tony Rice to be precise. It’s not a generic copy but a copy of a particular guitar which has been owned during its lifetime by the two greats; Clarence White and Tony Rice. (The original was modified with a larger sound hole and a Gretsch fretboard).

Some years after SC started producing them, a version appeared produced by Martin themselves (I think it was called something along the lines of the “LSH”). I always refer to it as “a Martin copy of a copy of a Martin”.