laptop - How determine keyboard variation when manufacturer changes it

When I decided to purchase Toshiba Z830, I specially noticed at photos that the keyboard was good for me (wide Enter, Left Shift, Backspace), you can query it at images.google.com, on most photos they're all wide. When I finally bought it (Z830-A2S), the keyboard was different, the Enter is narrow and the left Shift is "split" into Shift and backslash keys (probably 5% of photos at images.google.com).

Is it normal for manufacturers to change this during the production cycle or this can be variations from different contractors? But the main point, is it possible to determine this from the full model name or somewhere else without visiting a store?

It is not common for a manufacturer to change parts in a particular model during its production, but it does happen. Sometimes the vendor they use might run out of a particular part and they have to get supply from a different vendor. Whenever they do this, the manufacturers try to keep as close to the original specifications, trying not to go below the original "performance." For the most part, changes like these go unnoticed. You happened to notice the keyboard, but for all intents and purposes it isnt any less functional.

It can be disruptive though. Sometimes a manufacturer might switch ethernet chipsets on you, leaving you confused as to why your images fail to install, or disk drives are no longer being seen.