It's not a good idea.
Let me explain what happens, using the default colorset as an example:
Color ID 0 is red: 0.9 0 0 1
You plant brick 1 with color ID 0. It's red.
You change color ID to: 0 0 0.9 1, it's now blue.
You plant brick 2 with color ID 0.
Brick 1 is red and brick 2 is blue.
A new player joins the server.
He sees brick 1 and 2, and sees that they're both blue.
You save the bricks, and restart the server.
Both the bricks are now red.