There are many errors in the telephone switchboard featured in this episode. First of all, it's a toll switchboard, which would only be found in a telephone company building, and not in a department store.
The switchboard has calculagraphs, used by long distance operators to time calls; and key-pulse sets instead of the rotary dials needed on an actual department store switchboard of the era. The line and trunk lamps on the switchboard are illuminated and flash in a totally unrealistic manner.
Worst of all are the large, bright, bare light bulbs suck in front of every operator. No switchboard ever had such lights; if they did, it would blind the operator to the actual indicators.
The switchboard has calculagraphs, used by long distance operators to time calls; and key-pulse sets instead of the rotary dials needed on an actual department store switchboard of the era. The line and trunk lamps on the switchboard are illuminated and flash in a totally unrealistic manner.
Worst of all are the large, bright, bare light bulbs suck in front of every operator. No switchboard ever had such lights; if they did, it would blind the operator to the actual indicators.
Midge and her father spontaneously leave New York for Paris on the next available flight. This would have been impossible in the 1950s. Americans required visas for France, which involved getting oneself to the French embassy, and probably leaving one's passport for several days. The US Visa Waiver Program came into effect in 1988, and France joined in 1989, so it was only then that US citizens could travel to France with only a valid passport. (It is also not clear that Midge and Abe would have had valid passports, since I don't remember previous episodes indicating international travels for either of them, and, since transatlantic travel was a major luxury, people didn't usually go through the hassle and expense of having passports 'just in case' back in the day.)
When Susie calls to say a promoter wants to book Midge in Philadelphia, Midge says she's never been there and always wanted to go to Philadelphia. Yet in Season 1 we see her attending Bryn Mawr, which is a Philadelphia suburb.
Midge went to Bryn Mawr College, but tells Susie she has never been to Philadelphia. Bryn Mawr is a Philadelphia suburb that's just minutes from the city. That would be like telling someone you went to Harvard but have never been to Boston.