Did some more research on this:
"A 'neat' is a beef animal, and this oil used to be made out of cow hooves, hence the name. It is heavy oil and is known to rot cotton stitching on leather items that have been sewn."
"Saddle soap is a great solution for saddles but can actually harm upholstery leather. Saddles are made from tough, vegetable tanned leather that can take the alkalinity of saddle soap. It's intended to remove manure and related heavy soil from saddles."
"Contrary to popular myth, saddle soap is not recommended for cleaning leather couches. Like other everyday furniture cleaners, it is too harsh for most types of soft leather."
"Mink oil will leave furniture feeling greasy. It’s primary purpose is as a water proofing agent for hiking boots. It is not recommended as a protective coating for upholstery leather."
Understanding Leather Products
Based on what I've read, it seems for the type of leather that is used on boxing gloves, you would want to use a very small amount of neatsfoot oil, while being very careful not to get any on the seams. In addition to cotton seams, I've also read that using too much neatsfoot oil on the leather itself can actually cause the leather to rot as well. I havn't found any info on whether mink oil or saddle soap have this problem. I've used mink oil on shoes before but that's it.