I'd assume they are considered ranged weapons when thrown, but never used a spear.
You could test this by saving before a strong opponent, attacking without a skill, then reloading, learning / boosting a skill and attacking again, to see if there is a difference in the average damage value over a number of hits.
In a test save, you could use iZakaroN's SaveEditor
(or from Kiya's site
, with description) to unlearn skills, give yourself extra skill points or experience points (to meet level requirements), and possibly boost your constitution, so you wouldn't have to worry about your hit points. DAD's item editor
could be used to drop the base spear damage, if you wanted to accentuate the potential difference before and after learning skills.