Using external display without internal display connected

I recently tried to fix my macbook LCD screen, and instead of ordering the whole display assembly, as I should have done, i just ordered the LCD. To make a long story short, things got messy and until my new display assembly comes in I don't have an internal display to connect to the macbook.

Without the top clamshell and LCD attached to the computer, is it safe to reassemble and turn on while the computer is connected to an external display via my HDMI port? I just want to make sure the rest of the computer is functioning fine.

Thanks!