The Pioneer probes brought plaques (and later the Voyagers two golden discs) with a "pulsar map" imprinted on them. The purpose of the map is to make the position of the Sun clear for an alien intelligence, in the case they encounter the probes in the far future, by creating a frame of reference of known galactic pulsars with specified periods and their distance relations to the Sun.
Pulsars have nice properties for this goal; they can be detected from large distances (which gives a higher chance of some of them been known by both sides), their period is very specific, easily measured with clocks and can be unambiguosly matched to a specific pulsar (if known), and their period changes over time in a predictable manner (which allows for aliens to trace back the date of origin in which the map was made).
But I have a question. If pulsars are detected on Earth when their beams point towards us (the "lighthouse"/"becon" analogy) and there might be many pulsars that are not known by us due to us being ouside of the cone where the beam can point, then wouldn't the 14 pulsar used in the "pulsar map" only be evident for aliens in the immediate solar neighbourhood? Maybe a few pulsars can be observed by them in other parts of the galaxy but the 14 of them would cenrtainly not be the same set of prominent pulsars we know of, right?
What am I missing?