Cyclohexa-1,3-diene reacts with one equivalent of HBr. The 1,2-adduct and the 1,4-adduct are best described as

Protonation at C-1 gives the allylic cation over C-2, C-3 and C-4. Bromide at C-2 (1,2-addition) gives a bromide on the carbon next to a C=C between C-3 and C-4. Bromide at C-4 (1,4-addition) gives a bromide on the carbon next to a C=C between C-2 and C-3. Both are 3-bromocyclohexene, enantiomers of each other, so the 1,2/1,4 distinction does not give different constitutions here.