NOT KNOWN DETAILS ABOUT GLOCK 43 P80 LOWER

I'm puzzled. I bought a 22lr revolver a pair months ago, I planned to lengthen the barrel by about two inches so I requested where by I could buy a replacement barrel on the manufactures Site, they reported that the gun was registered to me by the atf with a certain barrel length and when I adjust which i would need a new serial range.Glock® forty