I completed both Raids on Hard over 20 times before a Gjallarhorn dropped for me. It was not even required when a team of 29s killed Atheon for the first time on Hard. So it is certainly not required for a level 34. And I have also completed Skolas without using. Last week with Small arms and Lightswitch I pretty much used Fang of Ir Yut for the entire fight. (On that fight it was far more useful than Gjallarhorn). There is nothing in the game that requires it.