Appropriate for what? different schools and periods of guns have pretty unique carving patterns. Study pictures of the guns you like and want to build, handle them if you can get access, then practice drawing the patterns you want. very early flintlocks had some Baroque designs but by the Golden Age the standard seems to be some form of Rococo, usually with acanthus vine/leaves... Now that doesn't mean you can't do whatever you want..depends who you are trying to please and whether or not you want a traditional looking gun.
"The Manual of Traditional Wood Carving" by Paul Hasluck is a terrific reference and tool for learning to carve rifles.
I have seen some Flintlocks that were carved with very unique and patterns with just about anything you can imagine carved on them. Where the carving flows and enhances the long slender look of the longrifle I think they are beautiful, just not too traditional.
Have fun!!
