When we were making bags, our standard was to have the buckle in the back, which made it a left hand carry. Although I am right handed, I like having the bag and horn on my left side.
We did offer the option of having the buckle so it was a right hand carry with the buckle on the back, but very few retail customers ever opted for that.
To the best of my knowledge, the company is still making bags the same way, 16 years later.
But, I agree, it is a personal thing.
I do not like having the buckle in the front, as I usually have a little pocket on the front to carry my powder measure in and also a little brass primer when I shoot flinters.
John (Bigsmoke)