Yes they are a Hollyweird invention. Started in 1939 when they cropped the barrel and made the big loop on a model 92 for John Wayne in the movie Stagecoach.
That's not exactly correct.
The true genesis of the large loops can be traced to early Calvary days at Fort Bliss. Calvary troops, on horseback, often trained up in the mountains and/or during colder seasons and they wore gloves, naturally. The OEM levers were not conducive to gloves being worn so troops had their blacksmiths enlarge the loops so they could be jacked, more easily, while wearing gloves.
How do I know this? Because my grandfather was a second generation Calvary troop stationed at Bliss. They were still on horseback when he arrived in the early 30s, but his father had also served there at the turn of the century and they were doing it even before then ... or so the story was told to me.
Now, there is some historical evidence to suggest that arctic circle explorers, who carried big bore leverguns, also enlarged their loops to fire with mittens - which was the genesis for the trigger finger mittens. But as far as which came first, Army Calvary or Arctic Explorers, it is a matter of chicken or egg.
Hollywood has never been a great innovator when it comes to either military authenticity or firearm portrayal. Not until the eighties did Hollywood ever even seem to care enough to hire consultants to get firearms, ribbons and medals, or tactics right in their movies. Thus the Dale Dye era was born. Before that it was not uncommon, even as depicted in "The Rifleman" to see six shooters fire two dozen rounds without reloading. And who can forget the famous "The Rifleman" episode where Chuck Conner rigged a six shooter on the end of a plank and a stick at the rear of the plank, (as a rear sight) to kill Vic Morrow (at long range) who had stolen his rifle from him.
Also, there was a lot more to that Rifleman rifle than just the large looped lever. It had trigger modifications as well - I forget the story behind that but I've read it somewhere. It was basically the same trigger modification that allowed six gunners to fan their pistols while holding the trigger down ... according to lore.
Another Hollyweird perpetrated myth? Showdowns at high noon.