Is this vintage DJ real? Help!

[danlee077]

Hello I am a new member in this forum and I need your help. I recently bought this Rolex from a reputable dealer without the official papers. In order to test the authenticity of the watch, I took it to a watch service center to open the watch, etc. They said the watch was real and the movement is the official Rolex movement. However, when I posted some pictures on Watchuseek.com, some forum members told me that the watch was fake and the dial and the bracelet was fake. I am now concerned.
1. IS this Rolex Datejust (watch is from 1979) real? or fake?
2. What does the "OT" mean before and after the word "Swiss" at the bottom of the watch dial?
3. Thank you for your help I really appreciated.