Are all factory Glock threaded barrels serialized?
 

I recently received my factory Glock 19 threaded barrel and was surprised to see the serial number.

Do they all have one or was this taken from another gun?

no they have one.

Not all glocks have serials on their barrel, but some of the latest ones do.

Most handguns I have ever seen that was made in Europe or made here from a European owned Manufacture has the serial number on the receiver, slide and barrel.

My G23 is my oldest Glock. I bought it new in the early 90’s. It has the serial number in all three places. My ISSC M22 which I bought last year does also.