Just tried it on my M3 Real running the Sakura eng translation.
1. Plugged in my SC Lite without a SD card in it. Booted in DS mode. Sakura says "no GBA expansion detected". I selected a GBA rom and tried to run it any way. It loads for a while, then boots in GBA mode.... but then the SC Lite menu pops up asking for a SD card. FAIL!
2. Plugged in my SC Lite with a SD card in it. Same as the above, except this time it boots into the normal SC Lite menu in GBA mode. FAIL!
3. Plugged in my EZ Flash 3-in-1. Sakura still says "no GBA expansion detected". FAIL!
So basically, no. The M3 Real firmware only recognizes its own GBA ram pack.
May I ask why you want to run the SC Lite through the M3 Real?
The only conceivable reason I can think of is to run the internet browser. Though I haven't tried the browser with the m3 Real + SC Lite, I'm sure a patched version of the browser WILL detect the SC Lite ram. I used to do this with my old R4+SC Lite combo, and it worked fine.
If you think that loading GBA roms onto the SC Lite through the M3 Real loader will make them run any better, then I really don't think that will work. I recall that the SC Lite has problems running GBA roms because of the type of ram it uses, so there are bound to be slow downs no matter what loader you use.
Hope this helped.