Certainly ticks most of the boxes for a HJ Sandman. It actually has an optional engine, the 3.3. Standard at this time was a 2.85L. Does it have front drums? These were also standard on HJ Sandman until 3/76 when discs became standard on most HJ.
Stripes are a no brainer. These were dealer fitment so they just weren't fitted.
The console brackets are the dead giveaway - if it has those factory fitted it is a Sandman. Note that HJ front bracket is different to HX-WB. Except for the GTS guards everything else on HJ Sandman was possible for factory fitment on a HJ Holden van, including the full headlining (although virtually unheard of outside Sandman in HJ). Blackouts were mandatory on Sandman, if it doesn't have those it has either been repainted or it isn't a Sandman. They can be buffed off though, but hard in some spots!

As Al says Chamois with black trim is pretty uncommon. I only have 4 x Sandmans like this, 3 x HJ's and a HX. All vans.

I have 14 x 6cyl HJ Sandmans recorded, and another 9 x possibles. 13 of the 14 are 202, 1 x 173. All 9 possibles are 202.