Your OG is always taken before you pitch your yeast so you shouldn't be taking it after you pitch a starter.
Your OG should be fine. 0.004 points is only going to equate to maybe 0.2 or 0.3 % change in ABV. Pretty negligible.
I think in BeerSmith there is a way to tell it if you pitch a full starter or decant first. I am not sure where that option exists though and what effects, if any, it has. I think it would only really effect your volumes.
I wouldn't worry too much.