That's a tough one to find a good answer on. The only 2 items that seem fairly certain, from what I could find, are that yes, the MA895LL appears to have the LED backlit screen, where the MB074LL does not. But I am not absolutely certain of it. The newer 895 may also have the ambient light sensor to adjust the keyboard, and the older not. The only thing I have found on multiple sites is that the 895 has wireless "N', and it seems the 074 has wireless "G". The newer one (if true about LED lighting) is listed as having better battery life, and that makes sense with the LED. The "Santa Rosa" seems harder to be sure about. That was a step up in speed when it came out, and with these processors having the same speed, I don't know. The 074 may have benefited from that too. Here are two links, from the same retailer that you can open side-by-side in two windows for comparing many of the specs. Just click on the Technical Specs Tab.
For the 074:
ecomElectronics.com : Apple - MB074LL/A
For the 895:
ecomElectronics.com : Apple - MA895LL/A
And if only one proved to be Santa Rosa, the "Santa Rosa" models use a faster frontside bus (800 MHz compared to 667 MHz). From what I have read, all the Santa Rosas were going to have wireless "N" also, which could imply the older one is not since it is a "G".
Sorry I couldn't be of more help, but maybe there was a little more info there than you had found. One of the other posters may have some better info.