Don't forget that the marketing machine will also work to turn public perception of those old guns as something that only criminals would use.
And/or ammo for those "old guns" would slowly become unavailable: Joe Walmart, the year 2113: "What? .45? No sir, I don't think ammo was ever made in that size except for the military."
OTOH, if the device can be retrofitted into an older gun, it can be removed as well. A little tougher to do that if the RFID is embedded into the metal of the frame.
Blessings,
Bill