Green Door and Red Rooster - open 7 days a week -
At these clubs, hit or miss, no telling if any couples will be there - busy nights usually Friday/Saturday.
Even if you call ahead, by the time you arrive they could be empty,, or busy. Just go and try it out
Check both their websites for special events, and other info.
You may want to consider a club like Couples Oasis- Like minded couples looking for couples! more of a for sure think

There are a lot of swingers in Las Vegas so go looking and enjoy !
I have never seen anyone in mask at either club, except on Halloween - I wouldn't worry tho, as Green door is pretty dark, and at both clubs, the people are all real cool and nice, in my experience
Just go have fun !
At the swinger clubs, walking around, pretty sure clothing is optional for woman, men need to cover up unless in a room.
Another idea, If you are looking for a specific age group, a certain look, I suggest looking for a couple to take with you Or take a sexy escort to show you around the club, etc. !! We make excellent tour guides
There are a few gals on here that have male partners too!
Hope you have a great time! report back here to let us all know how your first swinger experience goes