REMINGTON MANUFACTURING DATE CODE stamped on LH top rear of barrel, 2 or 3 digit, (month first, year after) these will normally only be the last letters as seen below, The factory says all barrels are date code stamped, well I have found some that are not, or if they are, are so erratic stamping that trying to decipher them is impossible. Both were taken off Remington 760s, with the one on the left, a 30-06 that I bought new October 10, 1954. The one on the right again a 30-06, but with a shorter barrel that I made into a knock around quad rifle with pivot mounts.(*) On 8/9/99, they stopped stamping the barrels with the date code.This was exactly the same gun as the 1100 in 12 Gauge, but with less costly birch stocks, and less rollmarking on the gun's receiver.These were simply cosmetic differences, however, and all 1100 parts in 12 Gauge fully interchange, including barrels and receivers.
The design was self-compensating to an extent not seen previously, in that any 2-3/4" shell could be fired without adjustment in the standard models, and both 2-3/4" and 3" Magnum shells could be used interchangeably on the Magnum versions.
They however continued to mark the date code on the end flap of the shipping box for shotgun barrels however.
They planned on using just the serial numbers to tell when the gun was manufactured.
You will notice the year code repeats itself, but over 20 years difference, so even if it was used on the same model, in all likelihood sights or stocks would be different which would indicate the different date.
You will also notice the month code spelling out BLACKPOWDERX, this is a common code in the firearms industry.