Mellotronists

I had heard somewhere that even though the Mk VI racks are compatable
with an M-400, it's not an absolute exact match...so I guess this
means the tracking is ever so slight and may make a difference with
reproducing the sounds...true or rumour?

The package deal would be great if someone wants a Mellotron with
extra racks, but I kinda wish the seller would offer the option of
selling the racks separate. Understandable tho' to offer it all as a
package deal and I'd do the same. (try and find a Leslie speaker on
eBay w/o the organ...!) It seems however that Optigan seller separate
the unit from the discs.