Yea for best growth exchange the air in veg as well, they need the C02. A little tip would be to put a pair of pantie hoes on the intake (always felt like a weirdo buying these, because children's work best for the size) they will stop bugs from entering the grow rooms.
I would probably skip on the charcoal filter for the veg room, but HSA makes a good point, they do start to smell a bit in veg, just not nearly as bad as flower, so it really boils down to your budget. Safety is number one though!
Cheers,