If anyone has 16mm prints of the episodes, those would have the original "night of broadcast" sound mix. To my knowledge, no alterations, other than the title of the Next Week preview, would have been made for prints sent out to for initial syndication.
Yes, I own ~ a dozen episodes in 16mm, and I have about half of the series recorded off syndication broadcast from 16mm film chains (which is the way TV stations aired 16mm films). These days, I'm glad I saved the old recordings.
The "Next Week" title card was changed sometime ~ 1978 when the copyright was reclaimed by Paramount under the Copyright Act of 1976. Also removed around this time was the NBC Logo at the end that followed the Desilu/Paramount logo. Other changes were made to the syndication package ... including the omission of the electronic theme in the opening of early episodes and the use of incorrect opening VO/main titles on some episodes.
While a normal 16mm print sent to stations was complete, sans the trailer (trailers were on different reels and edited into the episodes, replacing the "Place Trailer Here" slug on the film) often stations would rather poorly hack the episodes to allow for more commercials and never show the trailers or all of the end credits. Not much attention was taken in some markets.