New tires purchased in 2018 do not have standard dot code for date of manufacture. the code is printed on the ire as" cch7..k1710u-1. the tires are yokohama s drive. 205/55-r15. no one seems able to tell me the manufacture date. the tires are visually ok and have 4500 miles on them, but i am concerned as to how old they may be, and should the retailer be aware of the dot code? can you de-code the manufacture date?