Help Identify this AR-15

[solo]

I briefly caught the glimps of a pre-ban AR-15 for sale. It looked as if it was a SP-1, but the only marking I found were SWG on the side of the lower reciever. I'm not an AR-15 guru and only caught a glimps of it. What is the manufacturer of this AR-15???

 

[Nukem]

SGW=OlyArms, usually a lower marked SGW is pre-ban, so it could have been built with an SP1 upper on it.