No tangible proof, but...
I grew up in a very very small country town. Every Xmas we would travel to Bundaberg (QLD) to visit the fam. At one of those 'big-smoke-fancy-department-stores' (aka kmart, target or bigw) I found this cool red lamborghini that changed into a robot. Thinking this was very flash, I blew a good portion of my xmas spending money on it. That was pre-Dec 25th 1984.
(Was definietly not 1985, because in 1985 I had a few more transformers, had seen the cartoon, and had a TF comic).
Once again, though, nothing tangible to back this up.