There is no mention of where this was found in relation to the debris field. That said, there are not too many of these pieces left lying around.

So the question is; is this a plant or not?  If it is a plant then why the big deal about not turning over the black boxes?

FOLLOW UP: Missile confirmed.  See the second link below.

https://theconservativetreehouse.com/2020/01/08/iran-refuses-to-hand-over-black-box-from-fatal-boeing-crash-near-tehran-nose-of-sam-missile-discovered-near-crash-site/

https://theconservativetreehouse.com/2020/01/09/u-s-and-canadian-officials-now-confirm-an-iranian-missile-shot-down-ukraine-air-flight-752/