I've seen examples where this wasn't a 100% rule,but I was told long ago that one of the best ways is to take a close look at the center-drilled hole in the end of the pin.
If the hole was a precise #2 center drilled hole (anything with a cactus or numbered pin),it's SW.
If you have an un-numbered pin with a BIG center hole,it's PROBABLY a Kersenbrock. Tommy D.