We don't know the answer to either part of the question! It's an ongoing scholarly controversy, outlined by u/hillsonghoods in his Monday Methods post on premodern PTSD. Some scholars claim that they can identify PTSD symptoms related to war trauma in accounts of the personality and behaviour of ancient warriors. Others claim that this evidence is way too thin to support the diagnosis, and we have good reasons to believe that their experience of war was different enough that they wouldn't have suffered the same kinds of trauma that modern soldiers do.

Fundamental to both sides is whether it is possible, and if so, whether it is ethical to diagnose people in the past with a disorder that wasn't understood or recognised as such in their own time. After all, as explained in the post linked above, it is a conscious and deliberate decision to define certain groups of symptoms as a coherent disorder, and PTSD was specifically defined in order to give American Vietnam veterans the treatment they needed. PTSD is not a timeless reality that simply needs a label; it is a particular way to frame and treat responses to traumatic experience. It can be extremely helpful for sufferers of PTSD to learn that they aren't alone, and to come to terms with their trauma by learning about the experiences of others. But we have to recognise that trauma is differently defined and treated in different periods of the past, and if we don't have the same diagnostic framework in place we can't confidently say that the things we find are the same as what we call PTSD.

This is why the most recent scholarship on premodern war trauma has turned away from the "is this PTSD?" parlour game, and instead looks at the way responses to trauma and moral injury were described and treated historically, rather than projecting our own understanding onto the past. We can certainly see people changed after traumatic experiences in all documented eras of history. We can learn a lot by analysing how those changes were perceived and whether people who had suffered trauma received any support or special status. We can't learn much by saying "this is PTSD but they just didn't know it yet."