Fred, I own a 1972 Schwinn Paramount P-13. It is the all chrome version. I purchased it as a bare frame last year and assembled it with the properly dated components. I recently took it up to Waterford to have them inspect my work and replace the decals. Mark, the head engineer, and everyone else there was very helpful and incredibly knowledgeable about Paramounts, after all they are all ex-Schwinn Paramount people.
Personally, I think you should not add braze-ons to the frame. It is not difficult to mount a water bottle with clamps, or to use the original clamp type Campagnolo derailleurs. Part of the purpose of owning a vintage bicycle is to have the experience today that you might have had in 1971. If you need more information on what components would have been on the Schwinn when new, you can contact me, although you can also look through the CR archives as there has been a lot of discussion about this.
David Cooper
Chicago, Illinois