Hi all,
This is what I know from the catalogs:
Prefix 11 is for a front bi-polar light: two wires: for parking & direction light, white lens with prefix 11 !, fitting 2000 & 2600 Sprint .
According to Carello, it was also on the 2600 Spider, but this is not in the Alfa 2600 catalog. I thought that those Spiders used the different shaped Altissimo version of that front light.
Prefix 16 is for a front mono-polar light: one wire : direction light, orange lens, fitting 2000 & 2600 Sprint for the German and UK market.
In this case, the parking light was in the headlight.
Prefix 18 is for the reverse light: mono-polar with a white lens that had prefix 18 ! ( compare the different white lenses on post # 2 and post # 4)
Exception on the prefix: the black plastic plate and the nuts had always the prefix 11 for both the front and the rear.
I have no documents on the Junior Zagato, sorry.
Rgds,
Thierry