I was looking for the guitar bit. It was usual for Hendrix, but I cannot recall another guitar player using a strat upside down.
There are more left-handed guitar players than expected, and some of them had weird methods. Dick Dale, for example, was left-handed and played a left-handed guitar, but had it strung backwards, as for a right-hand guitar. He had learned to play left-handed on a right-hand-strung guitar, so had his left-hand guitars restrung.
There are also a lot of guitar players who are left handed but play guitar right handed.