Symmetry without screwing up UV's

[orbiter]

I am very new to this modelling game so I may be talking out of my rear end here.
I use Wings to make models for a space sim "orbiter" which in turn has its own format for models. To this end a wiser man than me has written a plugin which converts abc.wings to abc.msh. This MeSH file is a form of text file and from there I can see the numeric values of all the vertices / edges and such.
Surely wings must store this same information, all be it in a different format.

Would it not then be possible to copy something from 1 2 3 to 1 -2 3 ie. from X Y Z to mirror it at X -Y Z

I know I am a very little boy talking to the clever men but it would be most useful