He may well have been armed, it is unclear.
From the first report:
“Police say they found the gun in the front yard.”
It matters tactically if he was armed or not. But legally, if you say you thought he was armed, and was attempting to use that weapon against you or someone else, you are good.
Other things they may ask about, which can sound foolish, but can really matter in court, and are used as traps:
1) Were the decedent or you in an illuminated location?
2) Were you able to visually identify the decedent?
3) Could you judge the height of the decedent?
4) What kind of weapon did you think the decedent had? (A really trick question.)
5) Did either of you speak before you fired?
Court testimony is less honesty than ritual. Honesty can be used against you, which is why the ritual evolved. A pat, bulletproof answer is often far better than the truth.