Ok. I know a lot of people are having issues getting Mo Van Barr's bounty to appear. And there has been a solution released... IF you are willing to start a new game.
Here is the step from beginning to end.
-Start a new game
-Complete ALL available missions from Bonnie BEFORE doing any other missions.
-Once you complete all of Bonnie's, head to Armadillo
-Do the mission with the Marshal.
-KILL Walton. Do no disable him. Shoot that bastard right between the eyes.
-Head back into Armadillo and wait for the bounty.
-Complete it.
And now you have fixed the bug.
Or you can wait for the patch...
Whatever you prefer to do.
I have tried every variation and it seems like that is the ONLY way to do it.
I did not find this on my own.
I am merely confirming it works..
PS3: SerithKelevra
Soul Silver FC: 4297-5639-6263