Possibly. Concept art we have seen for Avengers 4 could have been made during Avengers 3 concept art, due to some overlapping pre-production work. Hawkeye set photos show a somewhat different costume then the concept art, so the concept art should be taken with a grain of salt.
What do you mean? We've only seen the bottom of his costume (legs)
![Screenshot_2018-07-05-21-31-14(1).jpg Screenshot_2018-07-05-21-31-14(1).jpg](https://cdn.imagearchive.com/sideshowcollectors/data/attachments/245/245063-00648d1b0c80af03e1fce5ca3f79f765.jpg)
and it tit for tat matches the concept art. with the rest being covered. So its currently on point. Hopefully it all pans out with the Mk5