After digging into stacks of receipts and invoices--going back over a decade--I solved the mystery.
The no-longer mysterious Rose of the Day is Madame Sancy de Parabère, a Boursault rose (according to the Old Rose Adventurer.) She was bred in France and dates from 1873-4. This variety is described variously by contemporary sources as "fragrant...very vigorous, climbing, early flowering" and "thornless...vigorous, hardy in difficult climates, one of the earliest to bloom," and "quite a spring bloomer with abundant flowers...large or very large, fragrant, semi-full and a beautiful bright pink."
It's all true.