Big Rock distributes to other dealers, one of them being my employer Selway Armory. Here's the thing about new firearms, some get test fired or sighted in with two rounds, others take 20. Or more. A rifle with no sights? Function test with a shot or two. Need to adjust a handgun's sights? That could take more than a few rounds. Manufacturers aren't going to clean every/any gun they sell, they know it's new. Their warranty says it works or they'll fix it. It doesn't say they'll clean it after making sure it works. Maybe they had to put in a new spring, new extractor, whatever, to make sure it functioned 100%. It has 30 rounds down the barrel? Brass marks on the bolt face? Functions 100%? Send it out.
We get calls every now and again accusing us of selling a used gun as new. Or somehow spending our weekends taking our merchandise out for a test run. If only.
Call Buds if you think it's used, but I'd say clean it and go shoot it. You can spend 4-6 weeks having it exchanged for another one. Why not spend that month shooting?
Just my 2 cents.