Hi Clive,
I can't find how to save the library as *.llb, but I managed to save it in 16.2 format. I'm also attaching sch-27516 in 16.2 in case you want to extract something from there. About the pcb symbol, allegro doesn't seem to have the option to save it as an old version, but I saved it as *.brd instead of *.dra. If this doesn't work for you I'll try to find an alternative.
Best regards.
Jorge.