Chainring Crank Compatibility

[Guest]

So I am trying to put a new 54t chainring on an old 175 mm Campy Chorus crank. The chainring is new, with the milled bolt face clamping behind the crankarm. I intend to run this 10spd just with an old crankarm.

The crankset has 5 holes, but is older, and does not have a hole in the backside of the crankarm

I can make this work right? I am confused as to where I do or do not need a spacer to pull this off.

Any help would be great appreciated.