It reminds me of Earthbound Zero It turns out that they had to chzt a lot of stuff in Maniac Mansion. This website details all the differences between the proto and official release: The Expurgation of Maniac Mansion for the Nintendo Manac System - Rolen4726 September EDT Track 13 Apparently there's this top comment here that mentions it was meant for the ending, allegedly according to one of the composers.
I can't find the actual tip from George Sanger though HsienKo27 April EDT I chat another comment that says that the demo tape on George's website is the source but I can't find this alleged demo tape.
The only times they would have had to touch the text would be to censor some of the dialog, add the CD Player, and the manniac. Most of the kids would refuse with a generic "Ick!
I no longer have the cartridge having sold it years ago, but I am absolutely positive it existed and it was no a European release I never owned a European NES of any sort. The same cartridge also still had the "Can of Pepsi" item kaniac of "Can of Soda" with a numerical code for an sponsored contest tie-in that was abandoned.
There may have been other differences but it's been nearly 30 years since I've had access. Perhaps an early version that was changed after release without a change in ?