If they used Hot Wheels tooling, wouldn't it be an exact replica? It looks to me like it was made in the likeness of the same show car but not made by the same cast.
they re-worked the tooling to have the front trim that wasn't seen on the HW org tooling and raised the lip around the glass to be a bit different but look to be the same tools.
From info and photos i have seen on Zylmex they have uses other old tools from other die cast companies like PlayArt, Matchbox, and yat ming. Bubble came out around 1973/74 in both the normal looking one and one with over sized wheels.
sadly not too much info is out there for this car so i could be wrong and it is a 100% in house tool not a Hot wheels one.