Defunkd

[Rico_Steeze]

So in your opinion what are the odds of this being authentic? That’s my main concern.

[jimmyj]

Low at the moment, simply because there is nothing to compare it to and several red flags. This is just the way we have to approach it given the limited info and mysterious nature of the tag.

[Rico_Steeze]

Okay, what are the red flags so I know for reference?

[jimmyj]

Mysterious Tag, we can't find another one.
2XL size in the 70s is less seen, especially with those robust measurements.
Print image is easily attainable and a perfect candidate for DTG print.
I didn't look into this too deeply, but I don't think fight cards generally weren't made into t-shirts then, usually a throwback of some sort.