Looks like I may be SOL regardless. Did some more digging and Apple has not extended raw support for several cameras in Lion even though they were updated for Mountain Lion. For instance, the Oly E-M1 raw support was provided for Mountain Lion but not Lion, so there is probably no hope for E-M10 RAW support for me. The last Olympus update in Lion was for the PL5. So, future Aperture development or not, I have to change something. I understand that companies may not want to support platforms forever, but my 2006 white iMac works just fine for what I need, so I am reluctant to upgrade hardware just to get RAW support for my camera, as I have no other reason to upgrade. I also know in my bones that supporting those RAW formats in Lion would be no big deal for them, but that's life.
Would it make sense for me, do you think, to change my workflow and convert my E-M10 RAWs to DNG, using some converter, and work with the DNG in Aperture 3.4.5? Is anyone using DNG with that version of Aperture? Any surprises I need to be aware of?