Hi all, new to this forum stuff so forgive me if I stuff a few things up 😬

Back in 2006 I purchased a van advertised as a '75 HJ SANDMAN 95% COMPLETE' for $4500 (if I remember correctly). Soon after purchasing I started on the rebuild, stripping it back to bare metal, removing any rust and fixing any damage (not that there was much) and laying a coat of undercoat on before I ran out of money, so I put it in the shed and it's sat there to this day!
I always figured it was a sandman cause of the full headlining but never done any other research into it.
Anyway I may be able to get back into it soon and I'm now trying to decide whether to go original or to how I want it, being if its a ridgy didge sandy then original it will go. If not, then to how I want it will be its future. So if someone could help me with the id I'd muchly appreciate it.

My plates are as follows:
HJ PANEL VAN
07/75 BHJ28538A
GVW 2200 SEAT. 2

HJ8WM70
157690.A
1901-19 V
567-15947
L31
M21
GV4
8M70TEL315468J

Would also like to decode the paint and interior codes if anyone knows them? TIA

Happy vanning!