Well, from your serail number, your shotgun was completed on a Thursday afternoon in August, just after lunch. A rainy Thursday.
Just kidding- here is some info from Remington:
If you will call or email us the serial number and model number we can determine the approximate age of your firearm.
Serial numbers were not required until 1968. For models without a serial number, we may be able to determine the age by the 2-3 letters that are stamped on the barrel.
Contact us through our Help Center by email or call us at 800-243-9700 Mon-Fri 9-5 EST.
You can view the history available on most Remington firearms HERE
Good luck w/ your 11-48. Have an 1100 in 410- cool little gun.
BTW, the letter barrel codes mentioned below will show when the BARREL was made. It is generally used to date rifles, but can be chancy with shotguns due to frequent changing of barrels.