As long as the cubic inches are permanently marked on the conduit body. Had an inspector burn me on that one once. PVC LB no markings but the guy is a notorious nitpicker.
Besides splices in an unmarked LB I have a problem with Electricians that over fill a LB.
Just last week I had a contractor that had a 3" LB with 4 350 KCMIL conductors in it.
Stamped in the LB was: Max no. conductors :3 - 4/0 .