Need some help deciphering. I have 5 Goodyear "Polyglas-F70-14" tires. The following are the stamped codes on the back of the tires under the "DOT".

MDLD Y4A403 (spare)
MULD BBB388 (RF)
MULD BBB388 (LF)
MULD BBB388 (RR)
MULD BBB218 (LR)

Thanks,
Sam