Welcome to the Bunnings Workshop community @JohnC5. It's amazing that you've joined us, and many thanks for your question about blockout curtains.
Was there a particular blockout curtain that you were interested in knowing if it was in a two-pack? Typically, most of the curtains are sold in a single pack. These are a single curtain that spans the measurements specified. For instance, the Windoware 1400 x 2500mm Hilton Ivory Blockout Eyelet Curtain is a single curtain 1400mm wide. If you had a window larger than that, you would purchase two of these, and they would hang on either side of the window.
Did you want to know if there were two curtains of the specified size in the pack or if the specified size was split in the middle to form two smaller curtains?