Rest at ease. Pretty much everyone I know from Ext. got in somewhere. My initial concerns about how the extension program might be perceived seem unwarranted.
If your GPA and MCAT are high, you apply on time and submit secondaries asap, you'll get interviews. Your personal statement, clinical exp, and research have questionable significance based on my anecdotal observations.
So basically, you can get into any med school you would have been able to get into otherwise, via extension. They can get you to the interview.
Personally, I wish I could have taken my classes at SMC, the professors are better, have more time, they actually have office hours, you can get a good letter of rec, the campus has way more student resources, way cheaper, and I believe for the average student to really learn science material it ought to be taught in a semester system. All that said, I don't totally regret going to Extension, it worked out, I was just kinda miserable and broke for a couple years.
With ucla, you're very much on your own, and with extension, even more so. If you can study and manage everything well yourself, learn via khan Academy and YouTube, etc, have alot of time to devote to self-teaching/practice, I think extension is a good option. Especially if you're worried how they'll judge the names on your transcript.
Ultimately, the quantifiable, objective, easy to digest stuff seems to matter more than the details, for most adcoms. I'd advise you go where you can attain the best GPA and learn well enough to kill it on the MCAT too.