E-Bay has two different auctions up right now for "period correct" TA steel water bottle cages, search under "ta bottle" and you'll see 'em.
Not mine, no connection, I've got my stash. They usually go from $25 - $35 bucks in these auctions, at least in the last two years...
Good luck old chap. Check that E-Bay feedback, it won't let you down.
Regards,
Bruce VR, The Eisentraut-lovin' AF guy on Guam, where it's always 80-something with morning showers...