I don't know that I'd be too worked up about the Broncos. They have had a lot of moving parts and used the 3rd preseason game, like many NFL teams do, to tune up their starting players. They may have been starters, but there was no specific game-planning in that one.
That being said, the game certainly was encouraging to judge the quality of the Rams' 2nd and 3rd stringers. Problem is, many of them will have minimal or no roles starting September 12th.
Hopefully, the Rams starters will be able to turn in on in game 1. Clearly, the Broncos starters didn't click at first.