I've never seen any kind of research comparing the two but I believe the answer if yes. An 18 month detection time can't have anything to do with the decanoate ester because it would have expired long before the year is over. For example Test decanoate can only be detected for 4-5 months....same ester.
One could agrue that Test is naturally occuring in the body but any esterless injected androgen is cleared in 48 hours. It is mealy the metabolites that remain. This is where I think the problem is with nandrolone. I believe the body some how or for some reason keeps recycling the nandrolone metabolites which give to the very long detection time.
Which could mean the detection time is the same for any nandrolone product.
ST