In the previous answer i was being a smart A but in my day all the parts were made of steel so I imagine a good magnet would gather all the pieces, then start sorting for serial number fragments. Possible to do? Maybe but not probable, IMO.
The inert grenade bodies are not serial numbered, and are often sold as gag items in the United States.
The key is activating the grenades, which is no small task. The fuse is key, as faulty fuses are as likely to kill the user as the people the user is intending to kill.
Note that three police men and *four* cartel members were reported killed by these “weapons”.
I would rather not have a “weapon” that is as likely to kill me as the person that I try to use it on...