They look to be well made, but there are some fine makers who can get you a nice hand stitched pouch in that price range, or just a few $ more.
Like the rifles it is hard to say what a 1760s southern pouch would have looked like, since there are no (to my knowledge) documented pouches from that period that were known to accompany an American southern longrifle. Lots of references to both though, so we know rifles and pouches were in use.
That being said, I think simpler styles persisted throughout the period of use of pouches so if it were me, I'd go with something simple, but well made. I think a simple squared or round bottom pouch, with a plain, pointed or simple beavertail flap would be fine. I have seen (modern) references to pouches of that period tending to be "longer than wide" but I do not know what examples that is based on - if so, I think we have to be careful not to extrapolate too much from one or two surviving examples - there was probably a wider variety than what those few (if any) surviving pieces represent.
I also second Art's recommendations on the makers listed. For example, I think Cal's and Ernie's bags start in your price range and their workmanship is outstanding. All of those makers listed are very good and there are some very good values out there in their work. I think any of them would be happy to discuss your project and come up with something appropriate for you - they are nice folks.
Guy