I see this topic has popped up again and many of the pics are gone. From what I can see there is only one kind of 2" barrel, as far as the Model 64 is concerned.
There IS at least one heavy barrel configuration that was offered in 2" length and that is the 9mm Model 940, a J Frame. If we compare the 64 to the 940, there is no doubt whatsoever that the 64 has a tapered barrel. Somebody had asked why anybody would want a heavy 2" barrel. I have a 940 and I shoot it a lot. Yes, it is heavier than the tapered barrel, but it points better and the recoil is more easily controlled for faster follow up shots. It really does make a difference, but the problem is that many are unwilling to put up with the extra weight, especially when you add even more steel in a Centennial configuration.
I prefer grooved triggers for fast DA shooting because I shoot with the pad of my finger and I don't want it moving around or slipping off the trigger. Rather than buy and re-fit the increasingly hard to find .265" grooved trigger I now cut two grooves into the face of the .312" smooth trigger and I find that I can live happily ever after. I have done this to my 2" Model 64. My 64 was scorned, neglected and possibly abused by its two previous owners but now it finally has a happy home.
Dave Sinko