The Revolution came out in 2006 (2007 model year), but your drive is from 2004 or earlier. Yes, it is pre V-1, and is known for its Stainless Steel sprockets.
You should be able to modernize your Drive. The V-2 components are much better than the V-1 and would be money better spent. The only reason to purchase V-1 equipment (IMO) is to replace individual V-1 parts that have failed. In any event, I believe you can re-use your sprocket shaft. Upon inspection, if you find it worn, simply flip it for re-installation on the unworn side. (Be careful not to over tighten your locking screw -- you can crack the spine. Tighten snug and use Loctite Blue to secure so it doesn't back out). Take a look at your other shafts as well. The drum shaft should probably be replaced if worn, since you're installing new drums -- this will minimize accelerated wear on your drums. You may need new cables/chains as well if going to the V-2 drums.
OR, you can save some money by replacing sprockets and masts only. Again, I would recommend the V-2. They use threaded masts and are much more trouble free -- probably similar price to the V-1s.
Don't discard your remaining good SS sprocket -- some people still use them and would probably love to have a spare. Someone may like to buy it from you if it is in good shape!
The full upgrade is somewhat pricey, but your Drive should last for many years to come.
PS: Loosen the knurled nut on your fins to drop them so that only about 1/8" is sitting in the slot. This gives them room to wind up on the masts and re-direct your thrust more to the rear of the boat -- makes it easier to operate your Drive and no loss in speed! Also, it looks like your rear mast is slightly bent backwards. You can straighten it, but it probably doesn't matter if you are replacing it.