Welcome to the Team Garry!
10B is the second week of October which is your build date. So inorder to be numbers matinch every cast part on the car should havs a casting date that is seven to ten days earlier or 09E or a 09D depending on how many weeks there were back in Sep of '68. And 10A as a proper date code.
16467 tells me you own an Impala two door convertible that should of had a V-8 under the hood.
JAN is for the Janesville, Wisconsin Assembly Plant
136189 is the Fisher Body sequence number which doesn't tell you anything other than the fact that the car was QC'd and isn't some type of factory experiment.
TR stands for trim codes which follow:
836 Gold colored vinyl bucket seats
V-2 paint code was for a Sequoia (dark) Green in color body 2 is your white top color