Open OpenIV or Codewalker RPF Explorer (either one, it's up to you)

Go to mods/update/x64/dlcpacks/concorde/dlc.rpf/x64/levels/gta5/vehicles/mq1vehicles.rpf/bac.ytd and open bac.ytd and click import and choose BAC_sign_6 & BAC_sign_7.

Once both are inside, save it and you're good to go.