870 police magnum manufacture date help

[Mbeerie83]

I just bought a Remington 870 leo trade-in police magnum but the barrel letters indicate 3 possible dates of manufacture!

Magnaflux letter= “C” in a triangle
Material ID= “7J” in a square
Final inspector stamp= X
Two letter month/year= BO
Final assembler code= 64
Barrel= IMP CYL
Test code= B
Receiver serial # = B6328**M

-is there anyway to narrow it down with the above information I included from all the barrel markings and most of the receiver serial number? judging from the BO marking alone on the barrel it could be January of either 1977, 1994, or 2021. I would like a definitive answer as to which actual year is the real year of manufacture! Can anyone please help a brother out?

[EmmaHarris]

To determine the exact year, you should compare it with other codes on the barrel and body of the gun to find more information.