I happen to have a contact that is an expert on lead seals, he really did not give an answer other than to say to contact the expert at ANS, and use him as a reference. I did so last night and got a response this morning from a leading authority on lead seals.
Thank you for your inquiry. This is indeed an interesting-looking specimen. I'm sure that (name witheld) is correct, that it is some kind of bale seal, or something very similar, but I have never seen or heard of a bale seal that used the Federal heraldic eagle design. Judging from its appearance and workmanship, I would have to suppose that this item would date from the late 18th or very early 19th century. It appears to resemble the eagle of the Great Seal of the United States (particularly in John Trenchard's 1786 version) rather than a coin. Although it uses Federal designs, I do not believe it would actually be an official seal. The workmanship looks a bit too crude for such a supposition, and you will note that the arrows are in the eagle's right talon, which is technically incorrect although it is a feature seen occasionally in Early American numismatics, as you are probably aware.
It seems possible to me that this seal is most likely to relate to New York City, in the late 1780s, when lead bale seals were still in common use there. The scratched symbols/numbers on the reverse look typical of what one might expect to see on contemporary bale seals.
Hope this helps on knowing what you found, I would venture a guess it is a item that a lead seal collector would be interested in, but no idea of value, you would have to check past auctions on lead seals to venture a estimate I guess. but it is without a doubt a super find to have in your own personal collection....
Don