Now that no less than our esteemed leader has opened the door, I’ll enter too.
You and I have also had this conversation off-Forum. You are technically correct that there is no such cartridge as the 45 Long Colt. However, I can tell you, as a long time shooter, that the term was commonly used and still is by some of the older guys, like me. We use it in a different context than what Chris noted. The “Short Colt” was the 45 S&W Schofield even though, that too, is a misnomer.
On a more practical side, how do you differentiate between the two cartridges headstamped “REM-UMC 45 Colt”. One being long and the other short??
As we die off you will find that the term “Long Colt” will be buried along with us. But there is a basis for using it. It is a legitimate part of cartridge and shooting lingo and should not be lost to history, like so many other things have been, simply because it is not technically correct. To me it’s no different than '06 or Deuce or Short Magnum, or any of the other terms used to describe well known cartridges, which you will not find on any boxes either.