Yep, that is what you should see under "About this Build" in the menu, so sounds like you are okay. Yep, don't change any IV assets unless you know what you are doing. Not sure how the amazon dl process works, but if the dl files are still on your system you should not have to redownload the files. (2 days to DL

, I download the game via Steam in less than 1 minute)
THere's still a lot of good folks around here, and activity sometimes comes in waves. Also, for some reason the weekend is a little less active. Strategy & Tips forum is where most activity usually is, and great place to learn the game and discuss it. Although, primarily discussions of the unmodded game. (If you really want a feel for this community, that is the place to be..as well as play some GOTMs and HOF games)
I think RevDCM includes an old version of BUG as well, so you should have some of the features when you use that mod.
I get a lot of satisfaction from the unmodded game, but did play a few mods years ago. RFC and Fall From Heaven extensively.