Is it legal to sale not for sale DJ only 12 inch vinyl records over 15 years old?

i would think they would be catagorized as "collectors" and should be worth selling- though the demand may not be what you expect. at one time they were for "promo" and since the years have past are now just like anything else- the "do not sell" means that they were free to the DJ's is all - there's nothing illegal about selling them