Just to add to that, you should never delete existing copyright lines, unless you rewrite the entire file from scratch.
I copied all copyright lines from a file if I took code from it to a new file. The only file "exception" is dlls/ddraw/direct3d.c in my new ddraw implementation, as I've re-written that file.
If I accidentally dropped someone's copyright line, just send me a note and I'll correct it. (Marcus, Lionel, Transgaming). But I'll try to get them right.
My first plan was to check the authors of every function / code segment took over(There's not really much, except of thunks and old IDirect3DLight/Material/Viewport interfaces, where the whole files were copied), but that's almost impossible as ddraw was mainly coded in 1998-2000, and Wine-CVS starts in 2001.