No I'm not necessarily differentiating between hull and armor, but there is an armor penetration stat on weapons and long story short that's higher for focused lasers. The rest of what I've said is pretty standard "theorycraft" for any game with different damage/cost/armor/armor penetration ratings.
Kibaru from what I gather, if you find a station selling a particular piece of equipment it's likely to stay in stock for a couple of days and then vanish again, so it's not a case that you'll always be able to get specific prefixes at a specific location. Otherwise we'd already have an extensive database of locations compiled by the community I'm sure!