Updated: Dec 2, 2022
The PDF is self-explanatory :-). It is said that Milt Sparks worked for Royal (Milt himself said so, a sewing machine operator) and while that's not impossible, from the date of Milt's becoming available to join the gunleather industry in '72 it seems more likely that he worked for Royal's successor that was Pioneer (Tent and Awning) aka Eubanks Pioneer that closed up shop that year.
Quite collectible but had Royal not existed, gunleather history would have turned out the same. His company turned out what were largely Heiser copies in styling and construction.
Read more in my book titled "Holstory -- Gunleather of the Twentieth Century -- the Second Edition" that is available at www.holstory.com and printed for you/shipped to you in USA.