You'd have to show me a photo of Robert Vaughn's gloves in "The Magnificent Seven" - since they're not ringing a bell.
However, if the real question is - were closely-fitted gloves available? - they were, and leather was commonly worked as all manner of fine leather things were or could be made.
How serviceable they'd've been 'back then' would be pretty identical to today - they are what they are.
Drawing historical documentation from the Silver Screen can be inaccurate at best.
The Directors want to put folks into the theaters and if that means a bit of poetic license is involved with the facts, well...
Movies didn't begin to approach realism until about the time Eastwood's "The Unforgiven" made its appearance - they were "clean" and "sanitized" far beyond the realities of the Old West.
"The Cowboys" , "The Tin Star" and "The Culpepper Cattle Company" made some inroads towards "looking right", but they didn't have the escapist appeal of the average "B" Western.
There are good Westerns, and even great ones, but they got that way because of the way they were filmed, the story line and the folks who acted in them - not their fidelity to detail.
Scouts Out!