PowerEdge R300 Support which L5400 ?

Documentation I have seen said the R300 support L5400 up to 2.33Ghz, thus I assume the Intel Xeon L5410 2.33Ghz has been tested to work.  Anyone know if the R300 will also support the L5420 2.50Ghz and/or the L5430 2.66Ghz?  Is this a case of the documentation coming out before the newer CPU's, or is there a reason they would not work, and the BIOS was not updated to support them?