Confirming a defect vs. dust in slabbed T206

[Ericc22]

Greetings,

I bought a card on ebay that surprised me upon arrival. It was rated a PSA 4 and I made an assumption about what that meant. The card appears to have a blemish on the background. This blemish is present on the scan provided by the seller and I missed it. So, entirely my fault for purchasing a card that had a blemish that I don't like.

So please see http://tinyurl.com/27dsrus. You'll see the defect under Dunn's left armpit. Also note that above his right shoulder is another white cloud. There is more of this above his glove.

So 2 questions:
- is this consistent with a PSA 4 rating? I am assuming so, and I know from this forum that there is a lot of variability within a rating value.
- I think that the defect is on the card but is there a way to confirm that it is not dust - I assume I'd have to have PSA check that?

I am obviously new to this. Rookie mistake! I at least now know to scrutinize the scans before purchasing. Any help on the above questions would be most appreciated.

Thanks!

Eric