In Moravian Gunmaking II, there are several with sharp corners. Most notable is the Oerter in Windsor Castle on page 161.
Also see:
The Marshall rifle on page 76 - pretty sharp
Attributed Albrecht page 91 - well worn, with rust pitting
Oerter page 106 - corrosion, wear, and rounded
Oerter page 115 - sharp
I could go on but my sense is that the guns that were captured by the British and others generally not subject to corrosion are fairly sharp cornered, and those that are pitted appear rounded.