5 bearing block will have a criss cross pattern on the side of the block under the manifold and 3 bearings are smooth. and should be red. (as i remember anyway)
petrol 5 bearings had a 5 stamped on the head, manifold side at rear. dont know if this was done on diesels, but it wont help if the heads been swapped. engine number may help with link in previous post, other way drop the sump off and have a look.
