no serial number = no way to answer.
I don't want to leaf through 6000 pages looking for "1148", so give us a clue. Who manufactured this gun? If you have one you should be able to tell if it is a pump or an auto. The Remington 11-48 was a semiautomatic shotgun offered in .410, 28ga, 20ga, 16ga and 12ga.
0091
50-500 USD or so
50-300 usd
1148 in 12 ga. auto, field grade, would probably sell for $200, if in very good condition. There is no such thing as a 270 gauge. It is a .270 Winchester caliber, in the 7400 Remington. In very good condition, it would likely $250 or so. The scope is usually a throw-in, and will only bring extra dollars if it is a Weaver, Redfield, Lyman, Leupold (unlikely). In that case...+$50 for a good weaver, $75 for a Redfield or Lyman, and $125 for a Leupold.
about $300. if in good shape
150-350 dollars
50-350 usd
100-400 USD
50-200 or so
50-200 USD