What about Goyet instead of Goyel? 
My book by Johan f Stockel states there to be a Goyel in about 1690s. This pistol is not from that time but Goyel could have been working after this as well. 
Brest is a city in France so "a Brest" is indeed the name where this person worked. 
 
Style of this gun would be 1720s i think.
		 
		
		
		
		
		
		
		
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