Some do... Some don't !
I don't... Can't see a reason for waiting.
The "waiting thing" is most common among pilots with a 737-300 background !
If I remember correctly, selecting the flaps without having the landing gear down and locked (green lights) on this type would sound the "Landing Gear Configuration Aural Warning" (which was really annoying), but it could be easily muted (just as on the NG)
