Ron,
I load all my own rounds, so I typically only run my .45 Autos through my 1911 and my .45 Colts through the Blackhawk.
But the kids use the .45 Auto cylinder a lot. When the whole family goes shooting (niece, nephew, etc.), it's easy to go through 1,000 + rounds in an afternoon, so being able to pick up some bulk ammo (or have their dad pick some up) is really nice.
In other words, I wouldn't break the bank to get the convertible, but it comes in handy!!
ps. mine did come with the 'S' marked sticker on the box and I'll look up the serial number to give you a range for comparison, but I'm pretty sure it was an early 2008 gun (I joined the forum to discuss hunting loads for this particular gun...).