406 variations

From the images below that I have taken from my own collection over the years, it appears that the first editions with smooth wheels had 'handles' or 'steps' at the rear, bottom left and bottom right. Still with smooth wheels, a few models are produced with the later casting which has no 'handles / steps'.

Then shaped wheels are introduced and all these that I have seen have has no 'handles / steps'. The two small low-set 'reflector' lights are quite distinct on early models but on shaped wheel models (and transition models) they are less clear and the left one seems to almost disappear.

There are some differences in the metal shaping around the tow hitch but I think these match the change of 'handles / steps'.

The casting changes appear to be consistent across the three colours.