De la Riva guard is present in the old Kosen Judo techniques, but I agree that a lot of the modern lapel guards, inversions etc are innovations in their own rightI believe that the most original aspect of BJJ is the open guard. Some open guards such as Ashi Garami are derived from older Japanese techniques, but if you take the more modern guards and even some that are, in this day and age seen as old school, you'll find some originals - De La Riva, Worm, Spider, Mantis, De La X and Lasso are just some of them.
The great thing about BJJ is that it's not complete and most likely never will be. There are so many new techniques and open guards that have popped up in just the last two decades such as the Ham Sandwich, The Truck, Banana Splits and Aoki Locks, to name some, although do correct me if they are older.
Also, I think Berimbolos and Inversions, are a pretty new thing in jiujitsu too.