to reply to Billyboil quote "Matching a bullet specifically to a Glock 17 is one of the ways I meant "specific" (since you know it is not, say, a Lugar)." from above, the Glock 17 can fire both the 9mm parrabellum and the 9mm luger round, i.e. the 9x19 round that was specfically designed for the Luger pistol. Also rifling techniques and tooling are very similar between manufacturors and identical between different models within the same manufacturor. I.e. it would be impossible tell the difference in rifling between a Glock 17 and a Glock 19(another 9mm pistol). Also what makes ballistic identification work is that all barrels have a slightly different rifling singniture due to tolerances in the barrel, tool wear, machine tolerances ect. this gives each barrel a unique fignerprint if you will. I believe technology has only evolved to and will only be able to sustain caliber identification and then confirming or eliminating if a round was fired from a suspected gun.
To add a little more as i said earlier Glock 17 fires a 9mm round, there are many many firearms that also fire 9mm including 4 models of the Glock. Berreta, HK, Sig Saur, High Point, Colt, Browning, Rossi, Smith & Wesson, Jennings, Kel-Tec, Ruger, and Taurus as just a few of the manufacturors that make a pistol chambered in 9mm.