Lovely child
Yes-Not only is that something you needn't bother with (Because amounts of preservatives and shelf life are not something you can do at home) but you could put that as the selling point 'no preservatives'
Also if you use all organic stuff you can call them organic too
So I'd put on the label-keep refridgerated just in case
also-you could sell the dough too-as 'put in the freezer and make your own at home'

They sell cookies like that for fundraisers (frozen cookie dough) and in a freezer they could certainly last six months