i don't recall .uucp making it into the actual DNS, but i remember our mail system used it as a trigger to do a uucp-maps lookup.
It was for a brief period of time as a pseudo-domain and placeholder for MX RRs for machines participating in the UUCP project. Mary Ann Horton (formerly Mark Horton) was in charge of the UUCP zone. http://tools.ietf.org/html/rfc976
uucp introduced a far-flung group of hosts, academic and otherwise, to things that were popular on the internet, namely email and USENET.
Once upon a time there were not Internet and connection to ARPAnet was restricted, which triggered into existence CSNET, BITNET, etc, etc.) and for many, particularly developing countries or small institutions, could not afford to pay for a permanent connection sort of a DDS 56K. BTW in Argentina we didn't have even digital lines, just nasty copper between some places.
i'm sure its an open debate as to if being in the UUCP maps also meant that you were "on the Internet", but many people seemed or seem to think this way.
At some time there was some sort of confusion everywhere, and also turf battles between different "networks", CSNET vs BTINET, etc, but people one way or another got connected and that was the goal those days to get as many people as possible connected via some network and at minimum be able to have electronic email. There were some popular sites that ran services such as ftp via email, archie via email, etc.
i recall seeing uucp going into not only south america, but the caribbean, south pacific and many other regions, much the same way that you describe it.
Many of the developing countries did their first step that way.
there were several organizations who were quite dedicated to using uucp over (dialup/X.25/carrier-pigeon) in order to extend email and USENET deep into the third world.
Yes we used what we had at hand, Rick Adams originally at SEISMO and later at UUNET, Randy Bush, the folks at Pyramid, and many others helped a lot to get people on board. Very interesting days :-), while visiting Glenn Ricart (SURAnet) at UMD I remember giving sort of a lecture about UUCP and the tricks we used to get connected to his undergrad students. Cheers Jorge