The ignitor is an plugin encapsulated one, the 115 you bought has a open board plugin, both are options on AELs website (as well as standard open board non-plugin) As for the welded ballast brackets, both my 125s have them as well so I don't really know about that.
I wonder why the 115's I see in Canada and have the welded brackets, the ignitor is held on by the ballast screw. Kind of odd.
I would like a 250 watt Ballast for my 115. Just to see how it looks.