I see on IMDb that there's a Lloyd L. Wyatt listed as "Pierce - Tank Commander", an uncredited role. I couldn't find any pictures of him to compare to Blocker, though.
I'll take this as an answer to my question and let it drop. Thank you.
The A&E bio of Murphy stated that he had severe DSS and slept with a loaded gun. When it became intense he would move to his guesthouse to spare his wife and children which would lead to stories about their separating. The rest of the time he was a likable and well-respected guy. He was also not an alcoholic, in fact he rarely drank.
As he was so young when he went into the service I can believe this; also the fact that this was considered something "real men" kept hidden rather than deal with. As bad as Vietnam was the problem was able to be brought out into the light and recognized as such giving those vets eventual access to mental health care