Is it normal or typical for the sear to have a (wire edge) It appears to be from the factory grinding? / assembly process.

Is is acceptable or advisable to use grease on the sear.  Potential problems?? Warnings??

After studying the USMC manual I have begun the process of learning how to work on my AR.
This was a major step. Looking at the diagrams, it looks like a lot of parts. I do have a better understanding of these parts and relationships now.
I started by removing the butt stock. Simple yes, but a place to start.
Then I diassembled the trigger assembly, and reinstalled it.

I decided to smooth out my trigger. I hate a creepy trigger. I don't mind a fairly heavy but resonably smooth trigger though. This transfers over from my experience with handguns.

I know better than to remove metal using a file etc, or alter these engagement angles.  

What I did do is a very light polish on the sear only to smooth out this wire edge. It sounded strange to me at first, but a retired Army armored taught me this. I applied a small amount of fine buffing compound to a piece of cotton denim fabric. I then in long strokes taking care to hold the sear surfaces flat against the top of the work bench slowly polished it. When my thumb nail stopped hangs up on the edge I stopped. I then carefully removed any remaining polishing compound. oiled and reassembled the assembly.

I applied a tiny amount of moly grease to these engagement surfaces.  I then dry fired the rifle a few times and reguaged the trigger pull weight.

I now have a much, much smooth fairly consistent 6 pound trigger.  I will post a range report when I get a chance.

If I'm not happy with the results I can always buy more parts.

I am thinking I won't be happy until I build my own rifle.........eventually!