I have also looked unsuccessfully for these parts from Mouser, Digikey, Newark, etc. Agree that the part numbers given in this thread are Whelen / spruce's "aviation" part numbers, which are probably 5X more $$ than what you would expect to pay for a similar Molex part.
An electrical tech I work with who does lots of crimping on all kinds of connectors over 25 years said he had never seen a crimp pin like these, they have only one "tab" to retain the pin in the connector body. Most have 2 tabs (one on each side). Makes me wonder if they are truly Molex?
Maybe these are made specific for Whelen so they can jack the price way up?