Actually it is the other way around....AC current ratings are higher then DC current rating for a given voltage. The reason being that it takes a much more robust contact to break DC under load this is why large DC contactors have arc chutes or bellows to help extinguish arcs.
Here is the contact rating off of a relay on my work bench for example
15A , 120VAC
The question is if it is rated for 120VAC, if it isn't marked as such then it isn't.