B::Deparse has documented options to switch of the reconstruction of if from and-op. I chose one of the waysą...

Maybe I wasn't clear enough: B::Deparse can show they're similar as long as you assume the output is correct. B::Concise can show they're the same, and the output will be correct.

Do you imply that a post-fix if is not a "statement" like pre-fix if ?

No. The statement with the post-fix if is not an if statement, but I was not implying it's not a statement. I was implying it's not an if statement.