You mentioning that the appearance looks like teflon makes me think of my own 870. It's an Express that was made in 1995. It has a dull blue finish (common to that era), which when oiled, does look somewhat like teflon.
This may help you date your shotgun:
http://www.remingtonsociety.com/rsa/...ns/barrelcodes
You can also call Remington and give them the serial number.