help w tolkien lotr first amer. editions

Hi anyone! I need assistance in identifying what impressions of the
first american printings (hmco) of the lord of the rings trilogy that I
own! I get no response trying to order the proper back issues of the
tolkien collector and I don't want to buy the descriptive bibliography
just to solve this mystery! All the books have dust jackets so that
should help witht identification points. The return of the king is the
only one with a date and it is stated 1956. It also has the dropped 4
and the droopy print on page 49. The two towers has $5.00 on the dj as
well as the rotk which has a differently printed dollar sign and 5.00.
Anybody up for the challenge?
Any help would be greatly appreciated.
They all have the same look about them so I would guess that they are
all from about 1956-57 or so.
I can do photos if that would help!
Thanks in advance!