The change from 151 to 144 was probably later than that... Schwinn Paramount road bikes still had 151bcd at least as late as 1968.
As for the bike in question, the poor quality of the pictures makes it impossible to tell where the bolts are in relation to the inner dia of the chainring.
Aldo Ross
<Classicrendezvous@bikelist.org> Sent: Sunday, October 22, 2000 7:31 PM Subject: 151 v 144 Campy cranks, wasRe: [Classicrendezvous] Campy Crankset
> Fortunately, there is a good visual cue to discriminate the 144 from the
> 151. With the 144, the inner edge of the mounting bolt is only about 1 mm
> from the shoulder on the spider. With the 151 mm circle, the same
> measurement is about 4.5 mm, or 3/16" inch. The eye picks this up very
> easily. This is particularly easy to spot if you just look at the
> chainring, which will have the big gap between the inner edge and the
> mountinb bolt for the 151 circle, and almost nothing for the 144. The
> shoulder on the web, and the inner diameter of the inside reinforcement on
> the chainring, are the same for both series.
>
> A couple of other notes:
> --> I think that the transition on the ROAD cranks was about 1964 +/1 a
> year or so. Track cranks continued the 151 circle for many years.
> --> 151 road rings are much less common. Downright rare,
> even. Particularly in smaller sizes (44 was the smallest offered, I
> believe), because most riders of the day used half-step with sets like
> 49/52 or 47/50.
>
> Enjoy!
> Harvey Sachs
> McLean VA, where the weekend was wonderful for riding