I don't think you can make those conclusions from the pics you have. The angles are different enough that it's difficult to tell for sure if it's just lighting or actual change. Add to that the oddity of press bikes not always being production bikes and who knows.
Besides, even if they deleted the sight glass, who cares? It's poorly understood by most and rarely used correctly. I'd have been more impressed if they changed the location of the oil filler to where you could actually stick a funnel in it w/o it falling out.