In the early nineties, Waterford began splitting the serial number with the first part of the self-describing serial number on one side of the BB shell and the manufacture date and sequence number (L89260) on the other side (BTW, L is November, not December; the letter "I" was skipped because of the possibility of being confused with "1").

The bike was made in the PDG facility, Waterford, WI.

I would ask the seller to send you a close-up of the bottom of the BB shell showing both the driveside edge and the non-driveside edge.