exhaust manifold

[cshaw600]

Hi went to fit my decat pipes i braught last year i have a 4.2 my decat pipes are 445
right size pipes but are longer than my cats so i presume i have 4.5 cats fitted previous was wondering if my manifolds are 4.2 or 4.5 my manifolds have SO223 and SO232 stamped on them any ideas thanks