I say it's legit, everything looks right, I would have grabbed it in an instant. None of the repro/fantasy crap is being done on old Chek seltzers like this as far as I know, since blank, unetched ones are almost impossible to find. Very common to find different caps on seltzers, as companies went out of the seltzer business their bottles were acquired by others. While it was too expensive to re-etch the bottles(although it did happen on rare occasions), changing the tops was cheap and happened all the time - It's probably rarer to find a seltzer bottle with a matching cap. Great find!
Cookie,....That bottle is legit as far as I know....Penn Digger will probably weigh in, as Bradford is both of our(s) hometown, and Tom has mentioned these bottles to me in the past....His collection has a pretty serious focus on Bradford Pa bottles. Nice grab for sure.
Nice pick up John. I have a mint example of this bottle. Your top is not original, which greatly takes away from the value. They are fairly common on ebay (2 in the last 2 weeks) with damage and switched tops, but for $15 you got a great deal. Often on ebay too, the bottoms aren't shown which are likely to be damaged/chipped. I am not one to collect anything after 1900 or so, but couldn't pass up a mint example of this local bottle. You got a great deal. If not a collector of cokes, I would advise taking the generous offer given as my mint example with the correct top was obtained for near the same price. Thanks for sharing.
The lettering looks like it was made from a hand-cut stencil, which is good, as opposed to the obvious computer-cut lettering on the repro posted the other day. I don't know enough about seltzers to say it's authentic, but it sure looks good. Especially at that price.