I think the question was more along the lines of "Is it possible to get them?" than "Are there any I can see at this moment?" If that is the case, then theoretically... yes. Hoatzin aren't listed on CITES, nor are they particularly endangered. If a range country will willing to issue and export permit and the importing country had no particular issues, then sure, they could be brought over.
The poor success that so many facilities have with hoatzin in the past (a few modest successes aside) has probably done more to protect the species from import than any laws on the books. Many zoos aren't going to import birds from the wild just to say they have "the one and only" - and many private collectors aren't going to take the expensive risk of importing birds that they suspect will fail to thrive.