All the original brats, up until the more recent era (2010+) used a mold that had “© 1988 J.F.S.” on the back, as shown below:
These also had “LIL’ SPORTS BRAT TM” stamped on the back:
In later versions, they added the “©NHL” to the stamp, but the body mold date was actually changed to 1986, reflecting the founding of JF Sports and not the date of the mold:
Another example, showing the “©NHL” and the 1986 combo can be seen here, which is even more curious as this is from a collegiate brat, specifically for the University of Michigan:
In later versions, the company name is completely removed from the mold and only a large “©NHL” decal remains:
In later versions, such as the Vegas Golden Knights, the “©NHL” sticker has gotten much smaller:
