The design for the gable box labels is not created for a specific label.
You can print the design on regular white sticker paper and hand cut them. You can then download the PDF file from Corjl printing multiple labels on a page, to save on paper.
Then all you have to do is attach them to the boxes.
Gable boxes for stickers in size 6.25" x 3.5" can be found for example HERE
(Affiliate links included)