Mellotronists

Nice looking unit; appears to be a stable auction regarding the 
opening bid & buy-it-now price. Looks just like mine w/the "M" 
Mellotron logo on the control pad and all (I wonder what Inspector 
Schwartz is doing these days...!)

It seems I see so many pictures of M-400s with different control 
knobs. Some look like pointers, others look like round dials with 
little indicator notches on them, others have a combination of 
different knobs--mine has the black pinch-type knobs. So what do the 
originals look like and were the styles consistant through the 
production run of M-400s and Novatrons?