OK, I did some more research on this, listening to shows all the way through the 90s into Furthur shows and never once heard prayin', although braggin' is sometimes pretty slurred. Even with the slurred ones, I never heard a long "a" sound as in pray. However, in the first time that verse comes around, I did hear a "laughin'" in this show: http://www.archive.org/details/gd1990-1 ... sbeok.shnf
For some reason I have always thought it was Laughin'.
In context, the vision of card table with players either laughin', or braggin' (in maybe a "can you top this" manner"), with wine bottles on the table, works for me... prayin' for a good hand seems like a natural fit also.
I'll have to give the studio version another spin.