Frazier didn't come up with the curtain rod story.
Oswald did.
That's what Frazier said
How do you figure that?
Later edit: Frazier would only have felt the need to come up with the story once it was announced Oswald was arrested but once he'd heard the shots came from the TSBD it may well have dawned on him Oswald didn't carry curtain rods to work that morning.
But the only story he told was the curtain rods story, so how does that make any sense if Oswald came up with that story and Frazier actually didn't believe it?
Btw Frazier left the TSBD before Oswald was arrested and he would have been in Irving by the time news about Oswald's arrest was first on the radio (at 2:40 PM). Frazier's sources of information were very limited from the moment he left the TSBD until he was arrested at the hospital at around 6 PM. So, when and how did he get enough information to connect the dots?