We could also be looking at an F1 hybrid too... Is pubescence a dominate trait?
I can't think of many hairy Annuums...
Doesn't look like a serrano to me.
Can you describe the pod shape at maturity?
leaf shape and nodes do look annum-ish, and yet the hair makes me think pubescent.
If you look closely at the flowers, there is a touch of gold near the tips... Would like to see another picture under different lighting...
The plant holds the peppers differently than the goats weed as well.
Goats weed points them up, these dangle.