I just came across some old info in my files that Matsushita made
equivalents of the NEO-5000 and NEO-8000, their part numbers S6135
(50 mm digit height) and S6136 (85 mm digit height) respectively.
Perhaps this is what you have.
I wish I knew how to tell them apart. None of them are marked very well but based on what I've read on this thread, it sounds probable that there were multiple manufacturers. Do you know of the Matsushita digits were also called NEO XXXX ?
Brian