Birds Of Canada Series $20 Note Possible Error

Hey folks, I got the chance to buy this note at face from a local business that puts aside old bills and coins for me. At first I only wanted the bill because it's less common to see in circulation these days. I then noticed it had a small dot next to the eight in the serial number. Did searching and found very little information classifying it as an error. Best I could find was that it was a very minor one. Under close magnification, it appears the dot is of the same ink as the serial number itself, not just a random dot of ink from a pen or the like . I'd give it a grade of VF maybe EF but that's pushing it in my opinion. Can you guys give me an opinion on the possible error?