No, that's not acceptable.
BUT, your suggestion pointed me the right way!

Here is a way to solve this conundrum:
-First turn off "Straight quotes to smart quotes"
-Then perform the conversion from single to double opening quotes with S&R "Replace all". (Important to copy actual opening single and double quote characters into S&R!)
-Switch "Straigt to Smart" back on
-Perform the conversion for the closing quotes. A bit messy because the need of avoiding genitive and contraction single apostrophes.

Thanks Guessed! You saved my day!
_Lup