Shels played Rosenborg too in relatively recent times, although it was a bit further back in time in 2001.
Shels lost the first leg at home 3-1 and drew the second leg 1-1. It was in the second qualifying round of the Champions League.
A highlights reel from the home leg here:
https://www.youtube.com/watch?v=jXw9WRChvnY
Rosenborg also met Bohs two years later at the same stage of the same competition and won the first leg in Dublin 1-0. They went on to win the second leg 4-0, however. Stephen Kenny was managing Bohs at the time too.
Dundalk will be the fourth LOI opponents Rosenborg have ever played, according to this: https://en.wikipedia.org/wiki/Rosenb...otball#Matches