Originally Posted by SenorFunkyPants
Historically a "model year" starts in Sept after the factory holiday when all the new tooling is installed for whatever changes have been planned. As the lead exemption for bearings ended in July 2011 it would be normal for the bearing material spec change to have been made for the 2011 model year (ie sept 2010).
However there may have been engines already manufactured or lead bearing inventory that needed using up at the start of the 2011 MY run - so the actual date of the changeover remains somewhat unclear as evidenced by the oct 2010 car still having the lead bearings.
Numbers on the bearings are proof while a blackstone oil analysis is inconclusive.
You can at least be pretty certain that all cars produced after July 2011 will be with the new spec bearings.
Just an FYI...the 2011 model year started a lot earlier (than Sept 2010) in Mar 2010. Note that 09/2010 through 02/2011 are referred to as 2011.5, and 03/2011 through end of sedan production are referred to as 2011.75 (informally, due to minor changes).
2011.5 M3 sedan 6MT, Silverstone, slicktop, loaded
2001 M5 LeMans Blue/Silverstone
2006 330i 6MT Red/black, ZSP, Nav, etc
2007 328i wagon Silver/gray