Bruce
Since you asked the question, I did not.
I also did a quick internet search without success.
Since the reply, I also went through my records from NRA pistol competition, including Pistol Commitee meeting minutes/records and Camp Perry history.
Same as you. I found nothing.
Many of the current .32 variations shot thru Pardini, Hammerli, and Walther target pistols, etc., often prove difficult in finding the right bullet/powder combination at 50 yards.
Often due to the small powder charge, reduced velocity, wind etc,. and of course trigger control and follow through.
I would think that maybe it was a result of someone who had the time and inclination, and was willing to put in the effort of finding a .32 that would shoot at 50 yards.
Maybe it is the Holy Grail .32 caliber competitors are looking for.
One more caliber to add to Star ability!