Tire done?

This Maxxis DHR2 is ~ 1 month in use with less than 200km. People told me it's dry rot. I suspect the seller stored it wrong and it's old. But how do I figure out how old it is? I found a hard to read code that "probably" reads 11-301RU-10. Is this helpful? Is my tire done or still usable? These long scars are on both sides of the tire, about 8-10cm long with multiple cracks on each side. The inside however looks fine from what I can tell.