I have an International frame that's definitely a 1974. You can tell by the serial number: the first digit after the W is the year ”ones“ digit. The axle-to-brake mounting hole distance is 367 mm in the rear, and 371 for the fork. Subtracting 311 mm or thereabouts for the center of brake pad track on a 700C rim, you'd need a brake with reach 56 on the rear, and 60 on the front. Add a millimeter or two, or make sure for yourself. For my money, it doesn't look like a set of 57 mm max reach brakes would work. Yes, there are drop bolts, if you can find them.

BTW, I think that your bike is a '74 too, since as far as I know, they didn't use that champagne color on the Intl after that year.