Do sprats need to be gutted?
It is safe to consume the guts.
Many people do.


More Info:

After digging deeper into the above article I spotted it contains the answer.
http://www.theguardian.com/environment/2006/oct/07/features.food7


  They're so small (only up to 12cm long) that they're often cooked whole - head, guts and all. If you prefer, however, you can open up the belly with your thumb and rinse out the innards, and prise out the gills with your thumb and forefinger.


Regarding their association with brisling, it seems that the two terms are synonymous (though somewhat contextual):


  Sprats are sometimes also known by their Scandinavian name, brisling, especially if they've been smoked and canned.