I need some help with an older Eagle Arms EA-15. It is a Coal Valley lower with a serial number 113XX. It's a flat top with an Eotech 552 mounted on it. I cannot find any info on the upper assembly. I am pretty sure it is a custom build. What this boils down to is I no a guy who is parting with some of his ARs and I'm trying to place a value on this one. I know that the pre ban eagle lowers are sought after. Just looking for insight and value of this gun.