No ones backpedaling, I've been in the business long enough to know anacs does not always cross at the same grade at NGC or PCGS, $4000 is a lot to lose on a crossover.
In my opinion, and it's just that... I wouldnt pay over $2500 for it. Explain to your friend that ANACS is not exactly the most "reliable" grader. I strongly disagree, and were all entitled to our opinions! I believe the old ANACS had a tendency to undergrade coins, and not saying this one is, as the pics arent really clear. Your best bet would be to try and haggle some. If your able to get it at $3,000 you did good, but i personally wouldnt go over that. If it has no real personal value you could easily recover you money pretty quick through an online auction (other than Ebay). I'm not associated with them, but Silver Trades out of NJ tends to get a high return for slabbed coins from my experience. I could see this coin going for $5,000 at one of their auctions, but ask Corey to feature the coin and put it in the middle of the auction if possiable that way you get the late crowd and the early crowd before people leave because of getting bored... Good luck, but keep us posted!
Resubmissions to NGC and PCGS often result in down-grades too; or they remain the same; or they upgrade. All three things are also true about coins slabbed by the old ANACS. The point is this - forget the slab, regardless of who it belongs to.