PBR does  sell the gottlieb one's and they will fit after modifying the outside and you would have to file out the hole centres as they are about  3mm to narrow compared to the Bally type,  I have not tried this but i think it would work, only if you can't get a new one. Another suggestion,1 get a new plain shooter sleeve , 2 drill out existing nylon housing to suit the new sleeve 3 insert into hole, A friend did this on his Bally 'Strikes And Spare" and it worked a treat