Simply apply the identifier markings to the hammer/striker of a revolver or within the barrel of said revolver just as applied to a semi-auto.
Below is info toward how microstamping is proposed to be applied...
All one needs to solve this problem is identify how their gun is microstamped and if it's at the firing pin/striker then swap that part out for an aftermarket or used source which is not microstamped.Microstamping - Frequently Asked Questions
What is microstamping?
Microstamping is a new technology that would allow police to positively link used cartridge cases recovered at crime scenes to the firearms and criminals that fired them.
How does it work?
The basic technology of microstamping involves the use of powerful lasers to make extremely precise, microscopic engravings on the firing pin or inside the firing chamber of a gun. Police at a crime scene can immediately read the microscopic serial numbers on the shell casings and link the evidence to the specific gun that fired the round. Manufacturers would decide what the identifying marks look like and where they're placed, making it harder for criminals to tamper with the firearm.
Source - http://www.csgv.org/issues/illegalma...tics/msfaq.cfm
If the barrel is microstamped then simply order an aftermarket one as well, for a semi-auto. Additionally some applied light filing or even acid etching of the metal would obscure if not remove such an identifier...all abilities within the range of an average 100IQ level criminal.
It seems with schemes like this and cartridge cataloging (MD) the assumedly educated pencil pushers have a focus on the low hanging fruit, at what ever exorbitant tax payer cost necessary.
IIRC MA has investigated toward applying the same tech here.