its not a buckle, its a little velcro keeper (very important to have believe it or not) It's never bothered me how it looks though.
If you are ordering a bunch of DAA stuff then its best/cheapest to order directly from their website, even with shipping its generally cheaper than local mark up. for the holster, I always check daves surplus first but after that its simply anywhere you can find it, many of the forum sponsors carry the DOH holsters or you can order directly from bladetech