The Fairfield Four is a black gospel quartet that's been together for more than 60 years. The three oldest members of the group sang a song in Oh Brother, where Art Thou, acting as gravediggers.
I suppose it depends on what you mean by "old-timey." This being Mudcat and all. Old-time music is usually considered pre-bluegrass string band music. If you just mean old-time gospel, then Wilco is right... it could be anything from black gospel quartet to The Stanley Brothers, with everything in between. There are a lot of stylistic differences in there, so it depends on your taste..
The thread that you included in you original posting certainly has a lot of good contemorary recordings of ol gospel.