I finished welding in the bottom of the new tail light panel today & came across some date stamps, & need some help deciphering them. The l/s reads ZBL 10 28W3, & the r/s reads ZBR 11 6 W8. I believe the L in ZBL means l/s, & the 10 & the 28 are the month & day the part was stamped, am I correct?. What do the rest of the numbers & letters mean? The body buck tag build date code is 25L. Any help would be appreciated.