Mark:

Here are the steps:
1) Download the quick_selection plugin.
2) Unzip the file quick_selection.rb, and place it in your plugins folder. That's usually something like C:\Program Files\Google\Google SketchUp 6\Plugins
3) Run (or restart) Sketchup, and open your model.
4) On the Edit menu, you should now see a new menu item called Quick selection... Choose it.
5) Under Objects, scroll down and choose construction line. Then hit OK, then Cancel, then OK. All your construction lines should now be selected.
6) Now open the entity info window (from the window menu). From here, you can choose which layer to place the construction lines on.

I hope I'm answering the question you asked
CB.