Two working women living together for years would be highly unusual in the 1950s/1960s. So unusual that if they were not a couple (as would be suspected) or related, the peer pressure would be enough to force them to end their domestic setting.
In the final three seasons, when Laverne and Shirley move to California, the exterior apartment house shots do not match the set's floor plan- specifically the bedroom and kitchen. The outside shows the bedroom is above the living room, but inside it is in the direction of stage right. The kitchen extends beyond the living room, stage left, and from the outside it just shows that the building ends at the living room.
The show was originally set in Milwaukee, famed for its brewing history. The title characters were bottlecappers in the fictional Schotz Brewery, so they are shown working along a brewery's bottling line during the opening titles. However, this sequence was obviously shot in an Anheuser-Busch facility, as the bottles shown streaming along the conveyor are the iconic 'teardrop' bottles used for Michelob beer in the 1970s. Anheuser-Busch, the St. Louis-based maker of Budweiser, never had a facility in Milwaukee.