Micky: "Winchester 73"
Davy: "Colt 45"
Mike: "Smith and Wesson 38"
But then Peter breaks this pattern with "Vintage '66," holding up a bottle of what is presumably champagne.
As I wrote about with "Monkees a la Mode," the same sort of joke is in A Day at the Race, where three doctors step forward to introduce themselves and give their credentials:
Johnson, Bellevue Hospital, 1918Franco, Johns Hopkins, '22Wilmerding, Mayo Brothers, '24
But then Groucho, as Dr. Hackenbush, gives the model and year of his car: "Dodge Brothers, late '29."