No, as each casino is free to select which version of the games they wish to use.
Generally, they don't seem to fluctuate much. For example, if they're running the 94% version of Sugar Rush, then all games from Pragmatic will be the 94% versions*. Same goes for Relax, PnG, etc.
When I start playing at a new casino, I always check games from multiple providers to see which version they're running. In most cases, I won't play anything under 96% as it's just a massive waste of time; especially with the high volatility games they're making today.
There really needs to be more focus on regulating the providers.
While things like eCogra are a good step in the right direction, more needs to be done, as providers are coming up with increasingly clever ways to keep everyone happy. If a provider shows an RTP of 96%, most people would think that it's a good number. What they don't tell you, however, is that the 96% mark was hit after a 100,000x multiplier that landed once in 10,000,000,000 spins.
Until they change how RTP is verifed, like instituting a set number of spins, etc.. games will continue to run at about 50% short-term RTP.
That being said, I'll still play a 96% game over a 94% game every single time.
*) Some games from Pragmatic (such as Sweet Bonanza, The Dog House, Chilli Heat, etc) have 95% versions as their downgraded versions. Likely because Pragmatic doesn't want some of their most popular titles** to take a hit once people realize that they're not playing the default version of the game.
**) Big Bass Bonanza has a 94.07% version out there. That a HUGE drop from the 96.71% default setting.