I have a cottered crank Centurion in my garage ready for sale on craigslist. Looks a lot like yours. The wierd thing on mine is the front derailer. You pull the lever back to drop it into the low sprocket. Everything is Suntour on the bike, with the exception of the Dia-Compe brakes. Not a bad bike to ride around.
Oh yeah, I broke one of the crank cotters. Had a spare on another crankset- anyone know where I can get replacements?