On first glance, it could be any one of the Miyata-built frames, all of which were virtually identical. The three water bottle mounts points to Miyata 1000 or Expedition or maybe Univega Specialissma? The main thing that sets them apart is the internal dynamo wiring in the Expedition. So, the little hole in the downtube makes me think you have the real deal there. The serial number is correct starting with "L" for 1983.

Tad overpriced, IMO, but a *very* pretty frame, updated in an intelligent manner. Maybe if the CK headset were free...