I am receiving a 4 ohm Celestion Neo 15 orange label tomorrow. I want to pop it in this cab for a try. How the hell do I get the front grill frame off? It has 2 little pull tabs (?) at the bottom. This has no flip top. It should pull right off, correct? I can't budge this thing, what am I missing? I am a doofus sometimes when faced with the obvious. Please help before I get out the crowbar.