I recently acquired a very funky and very beaten up'78 Stingray.
At some point the mutes had been removed, but the screws where present.
I got a replacement set from Ernie Ball UK
* and installed them today.
First I loosened all the strings a lot, then I removed the two hex screws that hold the bridge in place and the mute-screws. Then I lifted the bridge and carefully put the mutes in position
Put on the screws
And done! Like new
I actually got two sets, one for my 1979 fretless Stingray too: it had the mutes, but they were all dried up and not functional (I know I could have juste replaced the foam, but I wanted to keep the old mutes original just in case).
* getting the mutes shipped to Norway was a complete hassle!
Ernie Ball UK only ships to the UK and the Norwegian distributor had no idea of what I was talking about... In the end I had the mutes shipped to a friend in Brighton who then sent them to me.
I mean come on! Totally unnecessary... it's the Internet age, ship internationally already!