Eric,
The original lights were Marchal TP21
Renault 12 lights have a concave lens and measure 9" x 4.75" across the glass (front face).
Valeo/Cibies have a convex lens and measure 9" x 4.75" across the glass (front face) part no. (I think) is 4 70 078
I have seen both on Safir cars and the valeo as a replacement on original cars, have also seen an original car fitted with the 'GTD' Vauxhall Viva lights! /ubbthreads/images/graemlins/confused.gif
Hope this helps