David,I am comparing a Cat 1 V1 from May '72 to a 3 dot Cat4 V1 from '80 /'81 and the 3 dot is deffinetly wider at that point.Still due to there age I cannot say for sure that they have not been modified in some way by a previous owner,or a spa treatment but I will say that these 2 examples don't appear to have seen much use