Rare as hens teeth I would imagine, and of course being relatively old, and being made by Thule for TEAC rather than by TEAC themselves, there's no guarantee that the codes would standard TEAC - if there is such a thing of course.

The only thing I can suggest is keeping a close eye on the various auction sites and/or contacting someone with a remote and asking if they would kind enough to allow you and copy the codes to a learning remote. Maybe the guys at The Vintage Knob will able to help with that.