Existing vs New

I am over laying a revised plan over an existing and have the existing plan showing in a light gray. The problem is that the plumbing fixtures show in solid line weight. I tried "view to cad" and made a block out of it (existing) but the pumbing still shows as a solid line. What is the best way to gray out the existing fixtures? Should I choose each fixture and assign a new layer to each one?

In the block's dbx there is a selection for by "object layer" or "block layer", select by object and it should change.