[unruhjonny]

based on the speedo alone, it sounds like a 70-72.5 cluster.

there were two style black clock knobs, but that's getting into the minutia...

iirc the 70-72.5 used the smaller plug in the back.

now, if it's a hodge-podge, all bets are off.

look on the back of the housing to see if an early speedo was swapped in place of a later one.

Tachs (contrary to reproduction literature) were 8krpm through to 1976;
As of 1977, the limit reduced.
The 1970 tachs only have a single male connector - starting in 1971 there are two - because starting in 1971 you could get the 'unitized' distributor (precursor to the HEI that Pontiacs received in 1975).

There should normally be a printed (ink stamped) date on the circuit board.

The combination water temp & oil pressure gauge changed after 1972 iirc, but they are a direct replacement;
early ones had a temp reading @ 12=o'clock of 210 degree, the later ones were 220 degrees.

I hope that something here helped!!