RUMORED BUZZ ON P80 GLOCK 19 GEN 3 FRAME

I'm puzzled. I purchased a 22lr revolver a couple weeks ago, I wished to lengthen the barrel by about 2 inches so I asked the place I could buy a substitution barrel around the manufactures Web site, they explained that the gun was registered to me by the atf with a certain barrel size and when I modify which i would want a brand new serial selecti