There's an interesting question WRT open source hardware about just how much trouble the "providers" should have to go to to make sure "users" can actually use them. In the old days, vendors would sometimes provide "reference designs" for their more complex chips, and that would usually have a printed schematics and PCB layout "picture", plus sometimes a set of Gerber files so that you could reproduce the circuit board, and maybe a "bill of materials" so that you could know exactly which parts the board was designed to hold (a 47uF cap comes in a bunch of different sizes, for example.) That was ... something (and there are a lot of products out there based on reference designs), but if you wanted to make slight modifications of the design, it meant manually entering the schematic and PCB layout into some tool set that you owned; nearly starting from scratch.
The model used by the more "modern" open source projects (like Arduino, or the EMSL projects, or Adafruit) involves releasing the design files for some CAD package in a easily machine editable form. EAGLE is particularly nice, since CadSoft has EAGLE running on all the popular operating systems and has the freeware version around for anyone to use (for non-commercial purposes.) But it is certainly not required that design files be in any particular format, and even designs written in obscure and expensive CAD packages could still be legitimately "open source." (EMSL uses GEDA (itself open source SW), Solarbotics released their freeduino design in Protel format, and MDC released some of their designs in OSMOND, to mention a few examples.)
Likewise, it's not required to release open-source hardware designs in "ready to manufacture" form (gerbers, in particular. Gerbers pretty much suck as a descriptive/educational format, aren't easily editable, and are relatively obsolete from a technology point of view. But they're what the board houses all know how to deal with.) Asking the original developers to generate gerbers for you is a bit like asking the open source SW community to compile a program for you; not beyond possibility (witness the large number of binary distributions for popular packages), but not really within what you should EXPECT, either.
What kind of trouble did you have exporting the designs using EAGLE?
(and WHICH serial design were you talking about?)