I just took down my 75g FW (moved the inhabitants to a smaller tank), and that fixture was 4x96w, and I think that half the bulbs were 50/50. I'll make sure they were square and let you know tonight (pretty sure).
Sorry, the fixture I took down was 4x65. I didn't get a chance, but I believe I do have a 96w sq pin bulb. I was not home most of last night and didn't get a chance to review what I had.