Parts were sold a la carte with few exceptions. Cyclo-pedia one of the original mail order shops where one had to send payment in advance. They did advertise special group pricing in their catalog, but generally in standard sizes, say 170 mm cranks, 52/42, English threads. Bikecology also sold groups mailorder, similar pricing schemes, and started advertising prices... to the consternation of others. The whole group pricing marketing came in the 80's where more shops jumped on the mail-order wagon, some producing pretty comprehensive catalogs with detailed specifications, like Palo Alto Bike Shop and others. I have one catalog, I have to dig out, from a shop up in Northern California, a terrific resource. Like the old Spyglass catalog was for sailboat hardware in the 70's.

When the web took hold, things really ramped up, now they promote "build kits" too.

I do agree in this regard that there was a vacuum regarding the description of Campagnolo group names, shops filled the void, and some bicycle brands used the shorthand too, much easier for the consumer to comprehend. Reasonably accurate.
Sometimes there were alternate descriptions, like Super Record Reduced, or Super Record Steel, "Super Record" with steel spindles in the bottom bracket and pedals.