I feel like I'm nitpicking here, but it seems that Decluttr specialise is like the gumtree for buying and selling refurbished iPhones / Samsungs. I can believe that perhaps some people forget what model they might have (but even that's a bit of a stretch), but I don't believe that someone can forget what brand it is, especially if their website is involved. I mean come on, you either have one brand or the other - no one can miss the branding on the phone (in some cases), the box, the invoice, the startup (in some cases), etc. I question missing all of those signs, while still being literate enough to use a smartphone.
I also wonder where the stats came from. An online poll? A group of people in a mall?
This data to me is not enough to say that half of smartphone owners don't know what device they are using - the "data" and the statement with that are really far apart. That survey and this article is really scraping the barrel.