cazalea[Seiko Moderator]
20954
You can ask, but ...
The file now lists about 400 Grand Seiko models. My guess is about 20-30% might have display backs, but I have no way of knowing that apart from researching each model again on the web, and looking for images of the back, or if very lucky, finding a text reference.
I'd be happy to add the column if you have the data...
I built the spreadsheets the old-fashioned way by dogged determination and hard work. I might someday have time to research it, but not in the next month or two.
In the meantime here is the full spreadsheet if you haven't seen it.
Cazalea