The FBI is checking on whether Oswald's room already had curtain rods to determine if there could be a reason to take such rods to that location.
Nope! The WC are suddenly interested in curtain rods and, just one day after two curtain rods are given to the DPD for testing for Mr Oswald's fingerprints, are asking the FBI to help them with something.
Mr Rankin, in asking the FBI to "check out this story fully", bizarrely fails to mention the two curtain rods being fingerprinted; bizarrely fails to ask the FBI to determine whether any curtain rods were missing from the Paine home... Why not? Because all he wants from the FBI is help in closing the story down.
If you weren't incapable of independent critical thinking, Mr Smith, you would have seen this yourself without needing it explained to you!
How is your '275' and '276' explanation coming along by the way? Do let me know if you need assistance!