I picked a rusty International out of the trash last year. It had no original Campagnolo components, except the front hub, headset, and beat up pedals. Everything else had been replaced over the years.
So your original everything is really cool. I see your brakes are changed from the original centerpulls. Just clean yours up, and don't repaint it or try to fix the decals. It'll be great.
I disassembled the frame and dipped the rusted head tube area in an oxalic acid solution, and the rear dropout area, too. The rust just dissolves, leaving chrome and (usually small) pits where the rust was.
The paint looked really dull, but after using Meguire Paint Cleaner car wax, it came out amazingly shiny. I left the scratches and small rust spots on the paint alone. Patina.
This rust on the lugs and on the brake fittings all cleaned up. The fork crown is rough, but mostly shiny now.
The bike had been ridden on the front rim with no tire. It was all chewed up.
It appears to be approximately a 1975. But the serial number wasn't stamped all the way, and is unreadable.
More photos.