Yep, that's the one. I just decided to pull the trigger myself, I also got the $5 off offer.
You're right about the fact it might be cheaper on Black Friday but this is still a decent deal.
Looks like the DS218+ was $345 last year on Black Friday ($255 USD) and it was 1.5 years old at that point, so the DS220+ going for $350-$360 sounds about right.
So this is a $20-25 (+ tax) premium to get it earlier and guaranteed (no worries about it running out of stock).
I don't think you can go wrong either way. If you don't need it right away, go ahead and wait. Worst case scenario the price doesn't drop to $350 but maybe just to $375 or something like that.
If you do need it right away, this is a good enough deal that anytime other than a month before Black Friday, you'd be happy paying this much.
StockTrack is awesome but once the stock gets to below 3 like in your case, you can't really be sure the item is in stock anymore. It could be in the back like you mentioned, and the employees are just being lazy about putting it out, but it could also be that some employees have stashed it away for themselves to purchase later, or even that someone has shoplifted it and therefore it still looks like it's in stock.