This and the posts made by Blogd and davidmil are, in my opinion, very, very valid posts on this subject.

Davidmil's one comment is especially appropriate in this situation...the peep sight can become almost useless in lower light situations. Even if you can see the pin, without having it properly squared in the peep, you've increased the chance of wounding the deer at almost any normal hunting distance. Davidmil is also very forthcoming in his comments about having wounded a deer in just such a situation; I've done it too and as he said, its not worth it.

Until you've done it you'll probably ask the marginal questions like the one you posed in this thread...and you'll probably take the marginal shot. I say that with all due respect because we've all made mistakes and hopefully learned from them.

Make no mistake, I don't question your ethics, or the legalities, I question your need to shoot the animal under what surely sounds like marginal light.