Welding up cab air vents? should I or is there a reason not too.

[bguild]

question.. I have a 67 chevy and I am getting ready to do alot of cab work this summer.. My question is about the outside air vents that are in the kick panels of the cab. I was planning to weld them up and put speakers there.. I hate getting leaves and everything else in the cab. My other reason is that I will never ever use them. I plan to go with vintage air and I just wont use em. Is there a reason I should do this? Like rust etc.. Do I need to do anything to the outside part or do you think just make a nice patch to weld in the interior would work?