It was indeed recorded at Bob’s Place by Thom Manahan.
J. plays guitar on ‘Yer selfish ways’ and ‘Jugglers Rvenge’.
Found this on a German site:
"Zum Anschieben in andere SphÃ¤ren haben sie sich fÃ¼r 5 Tracks den legendÃ¤ren J Mascis geholt (der auch als Produzent fungiert)"
To get into higher spheres (they asked the legendary J. Mascis to assist them on 5 tracks (he also did the production)
On the album credits he’s just mentioned as playing guitar on the two tracks mentioned before, so I think there is something worth investigating here!