Patent 4077 - S6-E16
Corrected entry: Hawkeye and B.J. buy Margaret a new ring in place of the one mistakenly thrown out by Klinger. The peddler says, "Cheap setting, miracle glue". Cyanoacrylate glues were first discovered during WWII but were not commercially developed, as it was thought their quality of sticking to everything was a nuisance. It was rediscovered during the 50s but was not sold until 1958, five years after the end of the war. The second mistake is on this site: the episode was not called "Patient 4077," but "Patent 4077."
Corrected entry: BJ gives his home phone number as 555-2657; in the 1950's, phone numbers were generally given in a TWo-letter-five-number format e.g. "PEnnsylvania-6-5000" or "BEechwood-4-5789".
Correction: This is not a mistake. First 'generally' doesn't cut it - they might be the exception. Also, film makers are required by law to use unassigned telephone numbers, and have always used 555 as a prefix as such numbers are never used in real life.
They don't have to use the 555 prefix, it is just better that they do. They also used KLondike 5 or KL5 before the local area name was dropped.
Correction: 555 was never an area code. Original area codes all had a 0 or a 1 as the second number. 555 was an exchange that was never used for general public but it was used for some information numbers such as the time and weather. Usually Klondike 5 was used in movies or shows instead of 555 but either one is correct although in the 50's, it would be common to say Klondike.
Correction: The place name in the numbers mentioned actually translates to a three-digit code, the two letters merely were an abbreviation of that place name. It is simply an area code. The code 555 was reserved and never assigned to any real city in the US. To avoid people prank-calling numbers they heard in songs or movies, movie directors often used the 555 prefix. As detailed above, songwriters were often a lot less squeamish about using real, assignable phone numbers. There are several cases on file where phone numbers used in songs had to be reassigned and reserved, because people would call it "just to see whom it actually belonged to"
The place name and next number weren't the area code, they were the exchange. Usually giving the general neighborhood for the local number.
Last Laugh - S6-E3
Corrected entry: Leo Bardonaro supposedly left his hat at the hotel where he used BJ's name as an alias. General Fred Fox made BJ put on the hat to prove he was at the hotel. When Leo shows back up at the Swamp he has his hat back on.
Correction: He could easily have more than one hat.
Correction: This is not a mistake - he is using the word 'miracle' as a description, not a name. Americans call Miracle Glue 'Crazy Glue' (in the UK we call it Super Glue). It probably isn't cyanoacrylate he is talking about. The second 'error' isn't even a film/television error in the first place.