Why was this curtain rod sphere of interest ever developed in the 1st place?
If they were actually discovered in the TSBD ...why not just trash them?
Out of sight...out of mind

If they were discovered (as they surely were) by a Depository employee, then this option is risky. The employee might have shown it to fellow employees. They might be the kind of person who could go to the press about it if the 'investigating' authorities don't satisfy them that the matter has been properly looked into. Those 'investigators' framing Mr Oswald after the event do not have the luxury of working in a closed system-------there are real-world considerations that render the situation dynamic.
So what did they do? The sensible thing. They generated paperwork that could be shown to the person who found the rods at the Depository----------paperwork that 'showed' that the matter had been thoroughly looked into and there was nothing to see.
But more was needed by way of insurance against the person who found the rods causing a stink. And so a fiendish little plan was hatched to disappear the curtain rods found at the Depository into two curtain rods taken on-the-record from the Paine garage by the WC. Central to this little scam was the use of the digits 2-7-5 and 2-7-6. The Depository employee(s) had seen those digits on the curtain rods (precise length markings, possibly scribbled: 27.5 inches, 27.6 inches), and could cite them if they started kicking up a stink; what better way to discredit them in advance by using those digits as Ruth Paine Exhibit Nos.-------------"This person is inventing a story to make themselves feel important... They have gotten the numbers 275 and 276 from the Ruth Paine Exhibit Nos and misunderstood them as actual markings on the curtain rods. Unfortunately this case has attracted a lot of bogus claims." Quite clever really!
Mr Buell Wesley Frazier says he received an anonymous phone-call from a woman telling him that curtain rods were indeed found at the Depository. The evidence is that this is exactly what happened.