My mother's Lehigh Valley, PA shirt is the most washed and worn of all of them... and also the most "stereotypical souvenir" type.. the print on the front actually still looks and feels pretty darn good. I have others that are rougher and more cracked feeling but those are mostly concert *advertiser censored* from the mid to late 80s on second look.
I think this shirt is a fair representation of the majority of souvenir "gift shop" type shirts from about 1985-7 or so, which would be when she got it. I will post a pic in a bit if possible (I did pack them back away so it might be morning before I get them back out). The color of the shirt itself is still vibrant green, but since the detectives feel the shirt in question here is white (and we know it's stained) I suppose that's besides the point.
The ones that I have from the 90s are from the mid 90s and are stitched, not printed, so only the brand would be possibly helpful. I'll double check for details though...