Love a nice Raleigh Pro in the blue mink & silver paint scheme! The paint is in nice condition too, which isn't that common. Wonderful!

As noted above, the numbers on the pump are probably the gear sizes. It was more common to tape a table of gear sizes on the handlebars where you could see them while you are riding, but I guess this must have worked for the former owner.

Changing from tubulars to clinchers was pretty common for folks who weren't racing. 700C wasn't a common tire size in the mid 70's, so I'm not surprised that it is 27 x 1 1/4".
Similarly, making changes to get wider gearing is not a surprise either. The Sugino AT crank is a great option, since you can run it as a double or triple, and the chainrings are easy to find. I've got two bikes equipped with the AT, and am very pleased.

Looking forward to seeing how the rest of the cleaning and rebuild goes! Have fun!

Steve in Peoria