Certainly not regular maintainance, quite right...but..if he has had it a while, and its secondhand...it wouldnt hurt (assuming you arent one of those people who breaks things easily), to clean the noid and re-assemble it.
It is most likely taht teh screws are loose...but as I said, a steel manifold is a wise investment, as not likely to strip when you tighten up...SP do a higher flow, steel one as do NDZ.
Oh...and I'm not a Shocker owner...