Cheers for posting - I've never seen the brochure before
I have the same step on my Microbus 12seater

BTW, to aid elbow space across the back seat, the cross brace in the quarters was cut out during conversion and a moulded interior trim panel fitted in the cavity.
Mine didn't come with any of the seats, but the remains of the fittings for the buddy seats were present.
I know of another late twin slider 12seater - this one had all the seats but they were decidedly bench-like rather than proper seats, kinda like what you'd find in a locker room