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)
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