I just bought the 256GB Deck at the beginning of this month and it arrived on the 10th for $529. On the 13th they announced the OLED Deck and dropped the price of the 256GB Deck to $399.
I wrote to Steam customer service and asked if I could return the deck and purchase the OLED model for $30 more and they wrote back with two options:
return the deck, get a refund, and then buy the OLED model
keep the deck I own and get $130 in my Steam Wallet.
I'm not sure which option to choose. On the one hand, $130 is a nice chunk of change to buy some games. On the other hand, a brand new, bigger, and nicer deck is worth waiting a couple weeks and $30.