C.E. Harris wrote about the use of wadcutters in his exellent article, "Revisiting the Full Charge Wadcutter"
A quote from that Harris aricle:
"...The choice of a full charge wadcutter sounds strange today, but the load has an interesting history. During the 1970s and into the early 1980s 158-gr. lead RN and SWC standard velocity loads were issued by D.C. MPD, Baltimore PD, NYPD, LAPD and many others. Hollowpoints were deemed unacceptable during that era due to political concerns. I knew well several now-retired officers who were involved in shootings, and who had consciously carried wadcutter ammo, because it was “more effective.”
While this was strictly against regulations, it was not an uncommon practice. The officers involved seemed to get away with the excuse “we had just come from the range and that was the ammo we had.” A friend who is a retired Major in the Military Police reported the same, because wadcutter ammo obtained from the MTU pistol team was better than the Army’s M41 Ball. Unlike today, it was common for cops to shoot wadcutters on the range and change to LRN or SWCs for carry, as they were not required to practice with “duty ammo.”..."
Not surprising, I had heard remarkedly similar statements from old officers that worked in the northeast U.S. long before Harris published that article. The practice may not have been sanctioned but it certainly existed.