Yep.

https://tvtropes.org/pmwiki/pmwiki.php/Radar/LiveActionTV

All the Star Trek entries are hilarious:

Back in The '60s, U.S. TV networks, particularly NBC, wouldn’t allow women to show their belly buttons, most famously affecting Jeannie on I Dream of Jeannie. In the original Star Trek episode “Mirror, Mirror”, Uhura’s mirror outfit included a bare midriff and her navel is visible in several shots. The producers achieved this simply by having someone take the Standards guy out to lunch and lowering the bottom half of her costume while he was gone. The shots with her bare navel were edited into the episodes and evidently no one caught it.