You're absolutely right. When I ope about I am 100% saying "Whoop..", but it's clipped down to nothing. It's like a word with a silent letter in it. I'll say "column", and feel the N in my mouth when I speak, but we both know it isn't really there.
I live in Alberta now and am dealing with the conundrum of using "ope", "sorry", and "just gonna sneak on by..."