Campagnolo Vintage Gear Cable Guide 626/a With Bolt

Variation of the Campagnolo 626 cable guide. This one is for front derailleurs without a cable housing stop.
Early versions (1960s) have two dimples on the front guide (left) side. Later versions have a crosshatch pattern. This is likely from the way the stamping machine held the guide while stamping this feature.
The screw for these guides is similar, but not the same as the one for the front derailleur clamp.