Be aware that if you are looking for Historically correct, statements such as "doesn't look too out of place to me", have nothing at all to do with whether or not such an item was available in the 1700's. If you are looking to be historically accurate, you'll need to find some primary documentation of such a sight being used. I am not aware of any such documentation but that doesn't mean it's not out there.
If you are just looking for a peep sight so you can still use your flintlock without the sight being garishly out of place, both of the examples would do the trick with the dovetailed one being the least noticeable of the two. Either one is a better choice than no longer using your flintlock.
Twisted_1in66 :hatsoff: