Bro, if that Butt has been in a deep freeze, there is absoutly no reason to toss it out. 4 months is nothing. It will be fine.
Even in a fridge freezer 4 months should be fine, unless you have issues with your fridge. If the butt does not show visibal signs of freezer burn, I would use it in a heartbeat.
If it was ok when you put it in the freezer, it is still ok.