It will be a four digit number on the sidewall ex; 2212 the first two will be the week and the last two will be the last two digits of the year the ex is twenty second week of 2012.
My uncle is an engineer for bfg/ Michelin, and I asked this exact question, why do bfg tires show all the cracking so quickly that looks like dry rot. His answer was it is superficial and is only cosmetic, something about the compound of rubber they use. It is UV cracking. Every set of Michelin ltx ms tires out there does it too with much age on them.
Thanks guys, just wanted to make sure I was not gonna have a blow out at 60mph. I got these tires for my on road driving to save the TSLs for the trail