If you find a dealer or coin store that handels Whitman, you may ask them for ones with blank pages and a blank cover. They make lots of blank covers and pages for almost anthing you can imagine. For the info, they also make sheets of press on Gold or black lettering and numbering.
The bad part is these are Albums, not Folders. Therefore the cost would be substantially higher than for a Folder. l
I've used these blanks covers and pages many times to make my own type of Albums. For example I made an Album for several types of Nickels all in one Album.
You can order such items direct from Whitman but they charge massively for individuals but give great discounts to dealers. Also, if there is a Hobby Lobby near you, they too deal with Whitman.
And if you do go to the Whitman Web site, you could request a catalog. Might find it interesting that it is all owned by Harris. They make a large variety of Albums under different names.