Cool selection of Yesteryears Bob.
I know with the pre production models they often painted them white as this showed up any flaws in the casting. Then logically they tried out some colour schemes close to the colour of the real thing and may be every now and then something a little brighter to attract the younger collector but some of those colours are so way out for a Yesteryear model they would never be released in that colour scheme so why bother with it?
I'm sure if Jack saw them they would be straight out of the window and in the canal!!
It always surprises me that the earlier the model, the less prepros/colour trials there are of it. How many 1st series prepros do you see? Answer, none. 2nd series there are a few, and 3rd series a few more. When you get to the '70's there are quite a few, and by the '80's there are loads. You'd of thought that they knew how to make models by then, without so many trials in such big quantities. Some of the test runs were 200 models, which were supposed to be destroyed and recyclyed, but by then the workers knew there was money in them which is why we see so many these days. If anyone wants more info on any of these models, (although I realise YY's are only a small sideline on this site) just ask.
Please use a web hosting site (like photobucket) to store pictures so you can post them here, using attachments makes it hard to view the pictures when you have to scroll to see them. Seeing comparisons of models is hard to see with attachments too.