Congratulations on the
NFA find! I've got a stack of the old
NFA "Journal of Numismatic Fine Arts" (fixed
price lists w/ articles) that I bought from
FORVM. And a lot of other old catalogs purchased here. Several held surprise finds like that -- "in the wild," as the
provenance hunting expression goes.
Do you know of a forum somewhere where you can post a coin requesting others to post if they know of any auctions or published collections they may be in?
I wish I did! If you find it, let me know. There are a few people I email or direct message with about provenances. I'm always happy to try a coin or give any suggestions if you let me know.
There are other
provenance hunting enthusiasts out there. Not everyone wants to share their tricks (since we're often competing against each other to find lost provenances at
auction). But I think it benefits the hobby as a whole to share the info and assign
collection histories to as many coins as possible. I haven't really used the commercial services, like "Ex-Numis" (for a few reasons), but others have found
success that way.
It's tough for a single coin. You either have to find a die study listing known specimens, have some foothold to start with (e.g., if a coin is ex-Salton, it might be ex-Lockett, if it's ex-Lockett it might be ex-Pozzi or ex-Grantley, and published in this or that volume...). Sometimes you can find a recent (since 2000) record in
ACSearch or
RPC Online or
Wildwinds or somewhere that includes a piece of information you didn't know, and it opens a new line of
search.
But as you say, it really is "like looking for a needle in a haystack." The only way I know to do it efficiently is to always be searching for a huge pile of needles (keep all my coin
weights & photos handy) and methodically go through every haystack there is, hoping a needle sticks you in the eye. (Sorry -- that's as far as I should push the analogy!)
If you haven't, check out Steve M's rnumis.com:
https://www.rnumis.com/auctions_top.php (for tons of old catalogs available online) and, if you have any
Magna Graecia or
Sicily,
his amazing database:
https://www.rnumis.com/greek_coins_top.phpI also keep my own "database" of links to every published
collection and pre-2000
auction catalog I can find. (2000 being a cutoff for
ACSearch, where I just use their website.) I've shared some of mine for Alexandrian coins here:
https://www.forumancientcoins.com/board/index.php?topic=18927.msg779448#msg779448For
Republican coinage, I use the Richard Schaefer notebooks. I posted about it here:
https://www.forumancientcoins.com/board/index.php?topic=127540