Thank you for your question!
The ls_id in ls_dr8.tractor_n has recently been updated to the correct value and can be trusted online and through a notebook. Before, it had the incorrect release encoded in it, making it likely to not be unique against tractor_s values. i.e. it had 8000 for the release and not 8001.
Here's an example of how it encodes the release, brickid, and objid now.
select ls_id, ((release::bigint<<40)::bigint|((BRICKID::bigint<<16)::bigint|(OBJID::bigint))) from ls_dr8.tractor_n limit 10;
ls_id | ?column?
------------------+------------------
8797229300909075 | 8797229300909075
8797229300909568 | 8797229300909568
8797229300911473 | 8797229300911473
8797229368738762 | 8797229368738762
8797229300778048 | 8797229300778048
8797229300782092 | 8797229300782092
8797229300847940 | 8797229300847940
8797229368672404 | 8797229368672404
8797229368675255 | 8797229368675255
8797229368740305 | 8797229368740305
HTH,
Adam