Question [Q] Email: Red or Yellow Envelope?

Hi all,

I've been looking for a clear answer(s) all over and haven't had any luck. I hope one of you can help!

1. What is the difference between the "red envelope" stock email app and the "yellow envelope" stock email app?
2. Is the stock email app on the Galaxy S3 a Samsung app and not the stock Android app?
3. Is that the difference between the red and yellow envelopes? Red=Samsung; Yellow=Android?

It's been really frustrating to sort this all out, so any help is greatly appreciated.

Thanks in advance!