Are bicycle serial numbers no longer stamped into the frame? I found this bike ad which detailed the serial number of the bicycle for sale. I was surprised to see its simply a sticker which is far from the indelible stamped digits and letters on frames I'd seen in days past, usually chromoly or aluminum frames however. I believe this is a carbon fiber frame so maybe those frames can't receive the same treatment without compromising their structure?  Perhaps also bike manufacturers avoid the machining costs from printing a unique serial number onto the frame itself nowadays.

Is this how serial numbers are issued for bicycles now?
Barcoded labels like the one you’ve pictured are common and usually the most visible version of the serial number, especially on a carbon frame. 

However, there are usually stamped/molded serial numbers on the inside of the head tube and bottom brackets.