The question of "What pin is this?" is easily answered by first measuring the pin's diameter.
That will tell you whether it's a 5/16, 3/8 or whatever. Next is thread-count or 'pitch'.
Even without a 'thread' or 'pitch' gage, pitch can be determined by counting the number of threads
in 1" of length (of the pin). This applies to all SAE threads. Metric threads are a different story.
HTHs, KJ