Alas, you have encountered a shiny Pokemon!
There have been reports that the majority of all shinies have been found in the Friend Safari, possibly hinting the Friend Safari has a higher shiny rate.
The reason you may not have figured out it was a shiny was because Sawsbuck's shiny form and normal form look the same. (In previous games, anyway. Though a Pokemon mostly keeps their shiny form colours in later games)
Click here to see Sawsbuck's forms from all seasons.
So yes. It means something incredibly special. If the sparkling didn't look like this. Then I dunno. It should have been though.
Hope I helped. :)