Not sure, but my understanding is only the molded frame texture is different on the RTF Gen 3 Glocks, from the standard Gen 3. I can't imagine their being any functional difference otherwise. I wouldn't pay a dime more for the RTF over a standard Gen 3. The Glock 19 is pretty much my favorite Glock in 9mm. Not sure what's going on with the Gen 4 Glocks. I'm not sure the changes made were an improvement over the Gen 3. My experience with the Gen4 Glocks is rather limited so far. I'll likely never own one, the Glocks I have will last a couple of life times.
Savage