Well, as had been pointed out before, G and PG had wide berths back then.
(Consider that the movie "True Grit" with John Wayne was G rated, and he shouts out "Fill yer' hand, you son of a bitch!" and that was the mid to late sixties, methinks.
G might have tightened up some by the late seventies, but not so much that it couldn't show Ilia (at least from the neck up, or behind blurred transparencies) naked. Also, the movie had profanity in the form of either damn, or hell, and usually pretty emphatic. If that same movie were made under today's standards, yes, it would've gotten a PG rating, possibly even a light PG-13 depending on how today's modern moms and pops (who largely make up the MPAA rating board, despite their anonimity) feel about implied skin scenes.
Let's put this another way:
Take the Disney movie "Cat From Outer Space". 1978. Light hearted sci-fi comedy. It has McLean Stevensen drinking beer, a bookie, some smoking, even mild gunplay....it got a G rating back then....if it were made that exact way today, PG easily.
Raiders of the Lost Ark was a fairly graphically violent movie for a PG film. Just not enough to warrant an R rating in 1981, because of the context. Made today, the exact same way: Easy R.
Star Trek II: The Wrath of Khan....if it were made today exactly as it was in '82.... PG-13, guaranteed.
(And yet, amazingly enough, Star Wars Episode II: Attack of the Clones, which had more dismemberments and decapitations than probably any SW film in history..only got a PG rating.)
As for Persis Khambatta, looks like her hair grew back pretty well in time for the Stallone yarn, Nighthawks, and the cornball futuristic action comedy "Megaforce".