It very well could be.
Or he could get the Stark suit back, but (depending on how that's done) that could be anti-climatic to the narrative. After proving himself on his own, and becoming his own man, why go back? (narrativelly speaking - regardless of if the suit looks cooler) Perhaps there will be a third suit in the very end, a better one he makes himself; perhaps with the help of Stark's resources, but a suit he still makes himself which comes from who he discovered he is. Again, this is just speculation and I'm not advocating for this, but the early signs are that this might be a story of a kid trying to find his own identity (a "homecoming") and they seemed to be using the costume as a prop and metaphor for this journey. With that in mind, it makes sense that there could be a costume which represents who Peter has discovered himself to be beyond his insecurities (homemade suit) and external expectations of someone he looks up to (the Stark suit) and after a trial where he learns to put off those 'false selves' he creates a costume which will symbolize the hero he is and has become without needing to find his identity in the wardrobe (literally and symbolically) of Tony Stark.
Now the tricky thing about this is that they did such a great job with the civil war costume, if there is a third costume it has to be better. That might be challenging. Perhaps Peter will end up with a variation without all the stark bells and whistles. No crazy over the top high tech spidey tracers, no adjustable fitting features, no wings that actually make one glide, and maybe no black strips on shoulders and arms so as to appear even more true to the comics.
