As I recall it only winds in one direction and the caliber isn't as refined as some later ones.
The 330 through 355 movements can vary from 0 to +40 in three positions and be acceptable, with a maximum difference from fastest to slowest of those three being 30 seconds.
The 550 through 565 movements can vary from 0 to +20 in three positions and be acceptable, with a maxiumum difference from fastest to slowest of those three being 15 seconds.
So as you see, Omega expected better timekeeping out of the newer movements. There are a cubic crapton of factors why this could be, and I am no a watchmaker, so I can't tell you what those are. Only that the newer the movement, the more refined it is new from the factory. It is possible that either series of movements might beat these specs like a rented mule, but they are not required to. Also a nearly-new bumper might well outperform a freshly-serviced but worn out rotor movement.
So you have to take use case into consideration. Will you wear this watch once in a while for a day or two? Or will it be your daily watch?
One minute a month is two seconds per day. Neither of the series we're talking about is necessarily capable of that sort of timekeeping. Five to fifteen seconds a day on the wrist might be all you can expect.