One of the ideas in having a classic bike is that you equip it with everything period. The classiest pump you can put on a bike is the Silca frame fit, painted to match either the main color of your bike or the trim color. (it's plastic and takes well to spray paint). I used one for years and when I was using Specialized Touring II tires I rarely if ever got a flat. Now my classic bike is equipped with among the lightest training/racing tires and flats are more frequent. I carry a few black speed patches (glueless) and two plastic tire irons taped and wedged under the seat. I use a Zefal graph high pressure mini pump. It goes to 120 lbs with not much more effort than the Silca goes to 100 (more strokes though). It has a tiny guage (my opinion not needed). It weighs 115 grams and it came with a water bottle braze on attached clamp. I had to modify it to come closer to the centerline of the frame. It was designed to be used simultaneously with a water bottle cage. I just cut the brackets and drilled new holes to bring it nearer the seat tube. I only weigh 155 lbs but when my knees just graze the top tube (a bit of bad form but better than knees out), I can get my left calf to just graze the pump on the seat tube. I believe that some monster bikers can get their calves to graze an oversize aluminum seat tube when using a very knees foward position, but they have 17 inch calves. My LBS mechanic/racer says that only a rare few mini pumps will make it to 100 lbs needed to protect the rim if you are using 23 mm or 20 mm tires. The old Silca frame fit or the frame fit Zefal HPX, or the Zefal mini graph high pressure are your best bets. If you carry CO2 then you need to carry a spare tube or two too. Otherwise you would need some of the CO2 just to locate the hole in the tube before patching.
If I weren't playing around with racing these days I would have a Silca frame fit. Nothing is cooler. Garth