I was going through some of my files and found an appropriate advertisement to add to this thread from April 1913. This advertisement showcases these miniature bats, but I am not sure of their exact size. While miniature decal Louisville Slugger bats may have been sold at stadiums, this advertisement proves that they were marketed in retail stores just like normal, full-sized bats.
Also, in regard to the miniature Hank Gowdy bat, Louisville Slugger announced that they would honor Gowdy with a baseball bat in October 1914 following his great World Series performance. Moving swiftly while World Series fever was still out, Bud Hillerich actually called Gowdy at his hotel to get his signature that would in turn be used for the creation of the bat. I cannot say with confidence that the aforementioned bat was a miniature bat, but believe it to be connected with the miniature bat in the other thread.
Best,
Zach