I worked for a small-town beer distributor in Western Maryland from 1979-84 (Anheuser-Busch and Rolling Rock products). By 1970, most beer delivery trucks had evolved from the open and box bodied trucks to enclosed bodies with roll-up doors, such as that Peterbilt/ Pabst Blue Ribbon truck.
The change was for 2 main reasons, security, as theft had become widespread on the streets off the older trucks, and the change in product, as the returnable glass bottles delivered to bars gave way to products in steel and later aluminum cans, delivered to all types of retail outlets. The newer trucks could also be loaded more efficiently by forklift, speeding up delivery times. A pallet load of Budweiser 12oz. cans consisted of 96 cases of 24 cans each, at least 1-2 of these would be unloaded from my truck each day.
A reasonable 1970 beer truck could be made by combining the body from that Peterbilt to a typical 1970 truck chassis. That standard truck body has been made for 50 years by Hackney and several other builders.
In 1979, my employer had 1 1969 Chevy C-60/Hackney and 2 1970 Ford Louisville/Hackney trucks still in use. They were powered by gas engines, had hydraulic brakes, and were hot in summer and cold in winter. The Chevy could really run, while the 2 Fords were turtles.
The 69 Chevy was painted for the Rolling Rock brand, and the 2 Fords had the standard BUDWEISER logo.
A delivery truck, with details such as hand trucks and cases of products, along with a driver and helper, would be an interesting street scene.
In 1979, about 3 tractor-trailer loads a week would come in from the nearest A-B brewery in Williamsburg,VA.; about once monthly RR would come direct from the Latrobe,PA. brewery. We distributed in 2 counties with 3 trucks and about 6-8 employees.
In an ironic twist, the beer distributor building is now the main station of the local fire dept.