When to start putting the A/C gear in my car.

[green69rt]

Right now I am assembling the dash.  Nothing in the engine bay yet except the steering gear.  So, the question is, since the dash is out is this the best time to buy and install the AC box,controls?  I was looking at getting the Classic Auto Air  system.   I see in their instructions that you can do it with the dash installed but it just seems to make sense to install it now, before the dash goes in.  Or are there consequences to have the AC box setting there a year before charging?  Potentially, I could blow some freon into the box just to keep it dry. 

[krops cars]

I installed my factory ac before the dash. That way everything is wide open and easier to access.