From the components, it would be a middle-of-the-road kind of bike, price range around $150 in 1975. Certainly not a high end Paramount, and any other Schwinn didn't have a lugged frame. So probably European or Japanese. Can you see a brand name on the crankset? Are the rims steel or alloy? You might pin it down to the country of origin by measuring the bottom bracket shell width and figuring out if the fixed cup has left or right threads and the cup diameter and tpi. French, British, and Japanese headsets are also of different sizes. The head lugs are an odd shape that I don't recognize, and that probably means that it's not a Raleigh or Motobecane. BB lugs are pretty standard.
Oil is good, grease is better.
2007 Peter Mooney w/S&S couplers/Terry Butterfly
1993 Bridgestone MB-3/Avocet O2 Air 40W
1980 Columbus Frame with 1970 Campy parts
1954 Raleigh 3-speed/Brooks B72