with oil pressure running around 3 bar (45 psi) or thereabouts (not sure what it is on the 300Tdi - but not far off I'd think), if the seals were letting by, it would spray out at quite a rate....especially with a rotating shaft and impeller sucking it through too.....
Clean the hoses, fire her up and if they get a mist of oil straight off the bat, the seals are leaking.....hence why he says you need to rig up a 'catcher' to see how much is being spat out the turbo outlet into the induction pipes.