anterior means front. i am not a coroner but it seems to imply a shot from the front.
imho the clothes are also evidence and so should have been preserved and analyzed, especially given the “body was discovered” wording. the clothes can often give a clue if a shot came from the front or from the back, presuming the bullet penetrated the clothing.
if the bullet did not penetrate the clothing then in theory i would imagine that either the autopsy wording is inaccurate or someone needs to describe how a bullet can penetrate a shoulder without penetrating clothing that apparently can be seen in videos covering each shoulder.
so many questions...
Anterior is front.
Posterior is back.
Like Fore and Aft.