750.227c prohibits possession of a firearm in a vehicle, except as permitted by law.
750.231a(1)(a) permits possession in a vehicle with a CPL
750.231a(1)(e) permits unloaded, cased transport in the trunk.
28.425k(2) references a only concealed pistol with a BAC.
28.425k(3)(a) is similar wording to 750.231a(1)(e) to allow transport when you have a BAC.
Does 750.231a, where you are permitted to posses a firearm in a vehicle, have an exception for BAC. No. But, there is a huge grey area that I would not want to be a test case for.