I’m looking for some serial number information on the Remington PSR full kit with .338Lapua, .300WinMag, and .308 Winchester barrels. I have the opportunity to pick the kit up at what I think is a reasonable price. I have two to choose from, though. Both are NIB. One has a serial number of ECMSR000XX and the other has a serial number of MSR00XXX. Does anyone know the significance or history behind the two different serials? The ECMSR has 3 zeros and 2 digits. The MSR has 2 zeros and 3 digits. Is one more collectible than the other? Were the EC’s early units, and the MSR’s later units? Vice versa? Any assistance you can provide is greatly appreciated. One of those two kits is coming home with me on Thursday.