Heh, I've been waiting for a part to come back in stock for almost 2 years. I got a notice this morning and was immediately out to pick it up. OOS a few after ordering. Stuff going out of stock fast is no joke.
On the flip side, their high volume stuff usually comes back in stock pretty quickly, but might be slightly different, ODG furniture instead of FDE on the next batch, and so on. They were doing that practically every day on their last gen AKs, one day the good deal was on BLK, then OOS, the next FDE, then OOS, and so on. Three friends that picked up PSAKs during their closeouts, all three with different colors in the space of a week.