In other words, what different things would we expect to see under the two different hypotheses?
My impression is that Shadow71 is not rejecting the validity of natural selection. Rather, his position is that selection (natural vs. Godly) is unknowable. He believes God had some contribution to the selection process, but makes no claim of being able to produce evidence in support of that belief.
I think it all comes down to being more of a theological question. If God were to have been guiding evolution, would God have chosen or otherwise permitted the evolutionary history that we know as reality. To me, such a theistic evolutionary position comes down to being "God the tweeker" or "God the 'artificial' selector". God influencing the origin and development of the species not unlike how humans have influenced the origin and development of the dog.
Moose
Professor, geology, Whatsamatta U
Evolution - Changes in the environment, caused by the interactions of the components of the environment.
"Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham
"The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness." - John Kenneth Galbraith
"Yesterday on Fox News, commentator Glenn Beck said that he believes President Obama is a racist. To be fair, every time you watch Glenn Beck, it does get a little easier to hate white people." - Conan O'Brien
"I know a little about a lot of things, and a lot about a few things, but I'm highly ignorant about everything." - Moose