Drew,

You got me to open up Gaier's big work once again. He has picture of flintlock pistol. The picture is a small black and white image. But I am sure that barrel is damascus. It was produced in Liege, 1730 by Florkin. It is in the Arms Museum in Liegge, MAL 5209 Ad8.

I did another search of the Liege Museum of Arms and found this.
BAVIÈRE, 16th Century


So that is the earliest so far. From Liege, some time in the late 1500's.

Pete