I did some Googling on 
fecit vs 
faciebat.  It appears that in certain trades and contexts these terms are interchangeable and lose the implications of the difference in tense. In printmaking and engraving nomenclature 
fecit, 
faciebat, 
fect., 
fac., 
fec., 
f. are all the equivalent of 
made, 
made by or 
did.  Here's a site that suggests Michelangelo should have used FECIT instead of FACIEBAT in "signing" the 
Pieta because the letters are too squooshed in.  
http://100swallows.wordpress.com/2009/0 ... sterpiece/ 
Boyd Jacklin the luthier was kind enough to return my call and confirmed that in violin making 
fecit, 
me fecit, 
fece, 
faciebat, etc.,are all understood to mean the same thing: 
made or 
made by. He suggests that this might be because printers and instrument makers were tradesmen and probably not scholars. (Luthiers would have purchased their labels in quantity from the printer.) They may even have been a bit clumsy in the writing of their own language or dialect. Boyd told me of an existing letter written by Stradivari himself and fraught with bad grammar. 
I haven't given up hope that the mysterious Strad is a "witness."  Perhaps there are more documents from Corsby's shop waiting to be rediscovered. Maybe descendants of 
Victory's officers have family lore to offer or long forgotten dispatch boxes in their basements... 
The next question is - where is the violin now?  Does "Patch" or his family still have it, more than 40 years after that Sotheby's auction? Has it been privately sold since then? 
Tycho, it pains me to say I believe Nelson primarily meant the musical fiddlers in that famous bit of invective, although I think the additional meaning is quite implicit. I'll let you know why, when I answer your "Fiddlers and Poets" thread...
Gretchen