This is an ok representation of the gate, but I don’t think you should do the detail work with just a bump map and spec map. From what it looks like, you are using a medium res shot for reference, and it doesn’t look right on your model.
Is this for a game? Because if you are limited to polygon count, then that’s a different story.
Here is what my suggestion to you would be.
Keep the locks. They look great. Keep the shape of the ring. Use your texture as a reference, and start modeling the different areas where the symbols are. Don’t model the symbols on the ring though. That would be easier to model seperate, and placed on later. Not unless the symbols are depressed into the gate, I can’t remember. If they are, then you will probably have to model them on the ring.
I would look for a closer view of the stargate as a reference to model from too.
Here is a webpage of a guy who modeled the stargate too. He’s got some detail shots that might interest you.