The date code is on the tire, it will have the week and year of build, mine are 0413 meaning 4th week of 2013. Here is a flyer from Michelin, scroll down to see the code.
https://www.michelinb2b.com/wps/b2bcontent/PDF/3_TB_Service_Life_RV_Motorhome.pdf
Good luck in your effort to register.