I personally don't buy this story from the FO.
So, they tried to trade back into the 3rd round to take Armstrong, but apparently failed to do so. So the 4th round rolls around, pick-after-pick and they just sat on their collective hands defeated?
After failing to move back into the 3rd to supposedly grab Armstrong, wouldn't they try to then move into the early portion of round 4 to ensure they secured him? Not to mention it would have been less costly to do so than trading back into the 3rd round.
I think the guy they wanted was Tarvarius Moore who got selected at #95.