I agree that all the rookie WRs had their moments, both good and bad. It was a small sample size, but it looks like all are likely to be able to play at this level. Too many drops, but there must be an awful lot going on in their heads in their first time playing with the big boys.
Kumerow, to my amateur eye, looked every bit as good as the reports have suggested. He caught the ball with ease whenever it was catchable. I recall one fine move off the line that left him wide open but the throw made him back off to make a play on it. A few times he did not get a good throw, but was wide open on every target he had as I remember.
It looks like he may be for real.