Being that old it's probably 208v 3-phase but it could also be 277v/480v. Obviously the 120v outlet isn't 277v so in that case they'd probably have ran a separate 120v wire and neutral for the 120v outlets. Actually even if the pole lights are 208v(120v each of the 3 phases) they probably ran a separate wire for the outlets as often times they use a 30a breaker and 10 gauge wire(with no neutral) for multiple pole lights and you wouldn't want a 30a breaker going to a 120v outlet, not code and recipe for disaster!
Note if there are multiple pole outlets they are more than likely dedicated in which case you could use extension cords and a Quick220v type device(or a homemade Y-adapter) to get 208v.
Lastly, many pole lights get power when the lights are actually on, meaning when the lights are off you'd have no power to your outlets. It's possible each pole has it's own photo-eye in which case there would be power all the time but due to not wanting some lights on and not others during partly dark conditions, they like to have just one photo-eye for all the poles, in which case there wouldn't be power to the pole light circuit during the daylight. Thinking through this again I'd almost certainly think the outlets aren't a part of the power going to the actual pole lights but rather dedicated or partially shared amongst each other.