Attached Link: Baseball unis for MLB

I don't think so.  There's CoreArts' baseball uniform for M3, for sale at Animotions.  It can be converted to David using Wardrobe Wizard or similar programs. 

I'm hoping PoserWorld will come through eventually.  Steve made Poser uniforms for the Braves (see link) and at one point promised to make them for David, Luke, etc.  When PoserWorld makes clothing, they make them for a wide variety of figures. 

I don't think he's gotten around to doing it yet.  I wish he would.  I'm a big-time baseball fan.