I had some very similar to these and I had to dye them black. They worked for a long time but then started to come apart. I recently got some leather ones that are already black. I just had to remove the small pocket in front and color the treading, they are perfect now. Just pack the pouches with cardboard or foam to keep the form. Many on Ebay just like this one.
http://www.ebay.com/itm/WWII-WW2-GERMAN-MP40-MP38-LEATHER-MAGAZINE-AMMO-POUCH-BLACK-/122015428134?hash=item1c68afae26:g:pBYAAOSwmtJXX~uv