NSK was one of the manufacturers of the bearing. apparently they shipped the bearing to porsche without lube and with only one of the seals. porsche then filled the bearing and sealed it before placing it in the engine....
but now you've got the LN IMSB and your engine didn't grenade, so it doesn't matter anymore.
**EDIT** just saw that you mentioned there were no seals on EITHER side. so it's possible a PO removed the seals way back when (before LN's solution) allowing the engine oil to circulate hoping it would extend its life.
Who has done an IMS change (New Oil Fed Design Idea) - Pelican Parts Technical BBS