Vintage Single Stitch Military Tee Ass Kickin' Third Mac's Raiders Short Sleeve

I bought this at a vintage store and never ended up wearing it. I'm not sure how old it is but it has single stitch hems and is made in the USA. It's 50% cotton/50% poly. It does have fading and pilling and the screen print has cracks. Please see pics. The tag has it as a large but I don't see any way it would fit a men's size large today. It's definitely more of a small or really fitted medium. See pics for measurements. Very soft.