If its a Campag race triple... [own several]
the right arm has been designed to use a short BB ,
the 3rd ring sits on bosses rather than spacers.. they dont come off .

if the OP finds a older double crankset of same era,
the double sits on the same

111mm [or 115 if a large diameter seat-tube] the right crank arm
is different though from the side
looks similar ... the same 135 crank spider.

If you want the latest stuff, for the 50 34 combination,

then you pay the bike shop to strip out old everything
and buy the whole new set.

2 different sets of tools to remove 1 and install the other,
making a used once tools impractical cost.