Steamroller is not a refresh, it's a new architecture.In 2012, AMD released their Piledriver architecture, which is what is in all currently-for-sale AMD socket AM3+ CPUs (4, 6 and 8 core, 32nm).
In 2013, AMD released a refresh to Piledriver called Steamroller, which is what is in their current FM2+ APUs (4 cores only, 28nm).
Otherwise Piledriver is also just a "refresh" of the original Bulldozer.
Piledriver has recieved a number of smaller revisions during the years to offer better performance and less leakage. The last one was in 2014, "King Vishera" (according to The Stilt).Piledriver (AM3+, 32nm) has slowly been reduced in price as Intel has released new CPUs, but has not been refreshed.
FX-8370 and FX-8370E is of the latest revision.