I have looked at my GTA junior chassis stamping and in my case firstly the tops and bottoms of all the numerals and letters are level, as are the examples above. Secondly, the numeral punches which are all the same width (which explains the exaggerated down stroke of the "1", are contained within a "box" when stamping and as a result the stars are equally spaced each end of the number sequence, not squeezed in. Thirdly the "7"s on the Coy's car appear to have a tail at their bases which the others don't have. Finally the font for the "6" and the "0" appears to be narrower than the other examples.
Now this all may be able to be easily and satisfactorily explained, and I am not suggesting anything untoward, however it would be good to know!
After saying all that, Anthony's Rimicci's , above, example is yet another typeface on, presumably, a proper car and has different "star" shapes!
'57 Spider Veloce, '57 Lightweight, '60 SZ, '76 2000 Spider. '60 Sprint