You're correct that the big difference between the B17 and the special is the copper rivets/rails. While some people have suggested the hammered copper would avoid clothing getting snagged in the rivets, I think the difference is almost 100% an aesthetic choice. I just bought the special over the B17 for my upcoming tour and it was absolutely done as a 60 dollar vanity tax.
If I'm spending 2k on a new touring set up with panniers, racks, frame, components, saddle, lights, and camping gear for the trip... why not spend the 60 bucks and massage my eyes with the beauty of the vintage copper rivets every time I look at my bike? At least that was my thinking.
As for the springs thing, my personal choice has been to go without the springs because the leather saddle is itself designed for long rides without the need for springs. I've ridden a Brooks B17 before and I ride a Swift on my current bike (the non-touring bike I ride). I've never wished I had springs on them and I've ridden long days. Since the springs therefore add unneeded weight, the choice was easy for me to skip them.