You're taking a very big risk there. Preview might allow you to do that, but it will also corrupt your form in various ways. It's very likely that if you submit such a form to the IRS it will be rejected out of hand.
Yes, it would have been, actually. The LCD forms are completely different to the normal PDF files and you can't use the same "engine" to generate both of them. I do believe that they should not have been called PDF files, though, as they are not really that at all.