[tlg]

It's impossible to tell anything from a sideways (wrong ways) hanging bike.

Take pictures from the drive side with the bike on the ground.
Count the number of gears on the rear wheel.
Take close up pictures of both derailleurs and the shifters.

 

[tlg]

I can't help you at all on the value. But it's late '60's to early-mid '70's
Google "Campagnolo Valentino Extra" you'll find info.
Those Tektro brakes aren't originally. They're pretty generic but probably work way better than the originals. Unfortunately they probably reduce the value a bit.
Also the wheels aren't original. They're pretty modern low budget wheels.

Campagnolo Valentino Extra Rear Derailleur

Good condition. Vintage Campagnolo - likely late '60s/early '70s. Complete and fully functional. Finish is tarnished throughout.

www.hoopriderparts.com

VeloBase.com - Component: Campagnolo 2170, Valentino Extra