Obviously the original owner was a fan of the better American hardware and mounting. So he swapped out the tom MOUNT on the ZIM GAR tom to use the Slinger mount coming out of the bass drum.
So no, not a Slingerland tom at all. Also includes the Zim Gar badge.
That is a MAJOR score though! $75 for the MIJs would be great alone - cymbals and hardware to boot! Wow! Surely a highlight of your 'collecting career' if we can call it that :)