While I have never read the book (because it is historically inaccurate - so don't get too sad, because it never could have happened), there are many words that would signal a flashback. Flashbacks are a time of reflection, so there are many past tense verbs used. You may also see things like, "Back in my day...", "As I think back...", "When I was a young boy...", "As I remember...".
Answer:
it can be written in third person
Explanation:
if his name i joe then yes it is third person, if someone elses name is joe it is first person
Yes I do but no not in that way but the answer you are looking for yes but also no
