No, Momotaro use Zimbabwe cotton, I don't think Pbjs use cotton with a great provenance; they just slow loom weave it into great looking denims,with a big variety of finishes for such a small company.
Their kids wear is SO cute as well (no, I neither have nor want children, it was just an aside).
I wish my Pbjs would hurry up and dry..I'm in my Naked and Famous cashmere stretch and there's no competition..although (off subject), my custom Kurabo 21oz jeans - going since July 2012- are my best jeans to date in the last 35 years by miles...but still on the Holy Grail for best ever jeans!.
Basically, after all the waffle, I Think pbj just use regular cotton (it's definitely not Pima either)
Hope that helps