There is no right or wrong way to fit a bulb ~ so long as the current flows in and out again it will work therefore it makes no difference which wire is on which side of the connection ~ what this may do to the rest of your lighting circuit is another matter.
Seriously~ so long as there is one wire of each colour connected to the light fitting what does it matter. If your fittings have an earth that will of course need to be connected to the correct point.
DS will, of course, confirm that the right way to fit a bulb is with the root pointing downward (although some corms need to be planted on their sides to prevent water retention and subsequent rot setting in ~ anemones for example)