Possibly a good idea, but not necessarily.
Depending on when the cow tags are valid and when your bull tag is valid it may not do you much good.
Won't be much value in hunting cows in a unit in December when you're planning on archery hunting bulls in the same unit in September, and vice versa.
Mature bulls post rut are a whole different animal than cows.
Best bet if you're truly looking to "scout" for a bull tag is to focus on scouting for your bull tag, not running around spending time trying to fill a cow tag.
I say skip the cow tags and get to your area a week before the season starts.