Historically, 147gr 9mm was originally manufactured to operate subguns with their heavier bolts/springs. These were already plenty hot and could even damage some pistols.
+p and +p+ came much later, and there was no standardization to them anyways and IMHO, probably only useful in short barrel pistols.
I never heard of a subgun that required a heavier than 125 gr bullet for functioning. My experience with this goes back to the 60s. I'm not saying there wasn't heavier than 125 gr 9mm ammo made before the 80s but I never saw it in general use.
My first encounter with 147 gr 9mm was in the 80s. As I said earlier in this thread it's purpose was for use with silencers to avoid the sonic boom of the bullet. This was not a new idea as a 158 gr 9mm load was developed for Navy SEALs to use in the S&W "hushpuppy" variant of Model 39 during the Vietnam era.
Higher pressure pistol ammo was popularized when Lee Jurras started production of Super Vel in the 60s. This was the premier handgun ammo by the early 70s. The big boys realized this and managed to put Super Vel out of business. They marketed their ammo as "high velocity" or "high speed".
I was introduced to the "Treasury Load" when I went to work for the Federal government in the late 70s. Headstamps were similar to military like WCC and FC with the year of manufacture. Still no +P or +P+ headstamps. My the mid 80s these Treasury loads were marked +P+.
At least to my experience 147 gr 9mm ammo and +P and +P+ headstamps came about the same time in the middle 80s.