It certainly looks to me like the delta shields are actually part of the fabric, whether woven into it or silkscreened or whatever. I don't believe they were Photoshopped after the fact. That suggests they must have found a relatively cheap and easy way to do it despite all the "expert" opinions to the contrary. I just don't see any way to justify doing it otherwise considering how unlikely it is that anyone will even be able to see it in the actual film.
Which is why I am still more inclined to believe that these "costume patterns" are probably exclusive to the promo posters and not necessarily what we will see onscreen.