The seals might already be f*****. But since a restrictor is less than 50$...... it can't hurt to try vs dumping $ into a new turbo that you'd blow oil through if you don't get a restrictor to keep from pumping oil past the steel turbine fire rings.
In terms of seals are none like you typically think of like say a rubber O-ring.
The seals are nothing other than tight clearances and slinger rings/anti creep grooves on th rotating bits.
the turbo Center section depends on good drainage with no back pressure to allow the oil to drain down through the housing once it passes the two shaft bearings/bushings.
Push through too much volume or have a restriction in the drain and you end up pushing oil past the sealing rings