In general terms, yes, but it depends.
The rule is: You have to protect your straw bale walls from rain.
I don't recommend a cement based stucco because it can't breathe and eventually water vapor coming from inside the house will condensate and rot your straw bale walls.
You have different options for protecting your walls, it could be with big overhangs or verandahs if you are in a stormy rainy climate or you could use a material like Tyvek wich allows water vapor to pass but repels rainwater on the lower part of the wall.
You have to consider if you plan to catch solar energy, because if you do you'd have to calculate your eaves on your latitude according to sun and shading. A good tool for that is Google Sketchup.