I went through a deep MK1 and MK2 phase last summer. Youtube is full of some excellent early shows, 1970ish, and they do a lot of MK1 stufff still by then. I too loved the BO Ludwig but for the Machine Head recording he went all Silver Sparkly by that time,..... and recorded in a closet.Purple Mark I did some cool stuff but they were trying to find their style. I always refer to them as Psychedelic Elvis because of Rod Evans voice.
I loved the kit he used on the early stuff, Black Oyster Ludwig 1 up 2 down, pretty sure he used it to record Machine Head.
I saw a recent interview with Ian and he has not kept any of his older Ludwig drums (!), maybe one snare.