[Identify] Help me identify this Vintage Rolex from the '20s.

[lukehh]

Hi, new here, but I figured this forum would be the best place to ask such a question.

http://i.imgur.com/ia2bUHo.jpg

Here is the watch in question. I have very little information on it. A quick google search tells me it's most likely from the 30's, but could be as early as the 1920's. I would love to get a reference # which I can't find anywhere. An estimated value would of course be awesome too.

Thanks in advance