Most of the FHLBanks classify each member by the method of pledging collateral into one of three collateral categories: blanket lien status, listing (specific) pledge status, or possession (delivery) status.
So, yes, if you are being changed to delivery status, they want the collateral. I'm sure there has been correspondence with the bank.
You may find this useful:
http://www.fhlb-of.com/ofweb_userWeb/resources/lendingqanda.pdf