There'll be a bunch of certain items for sale as people upgrade to kunark ones, these will be worth less, so yeah, it might be worth selling some of it. Some items will retain a decent amount due to what they are. Even with kunark haste items are fairly rare so fbss will still be 8k+, it will come to supply and demand as it always does.
Jade maces will be the new EBM
[You must be logged in to view images. Log in or Register.] they'll be selling for quite a bit 12k or so prolly.
Just wait and see.