Yes, you may place decarbed hash oil (shatter in your case) into any edible or coconut cooking oil with great results.
Most shatter I see is indeed NOT decarbed (easily identified by labels on the product), however it's very possible that yours could be completely activated. There are several factors to consider but your best bet would be to ask the manufacturer how much of their shatter is activated for oral consumption.
Not having this information (THC, THCA levels) makes most concentrates a crap shoot for edibles, meaning you very well may waste your product if you can't gather this information first. It's not like you can just look at it and tell like you can with flowers (bright green colors is a dead giveaway the flower is NOT decarbed).