Safety switch question

[Joseph Scott 0]

I just found a safety switch lever which was drilled through 1/16" centered in line with the small plunger, apparently to vent and prevent oil "locking". There are several other small vent holes for this purpose but this is first I noticed on safety. Has anyone else seen this? I don't know serial number of gun. I think it is original but wonder if it was an early or late design change, or just a trial.