PTS1,
I sure hope your rifle shoots cloverleafs, but I wouldn't expect it, with any sporter rifle! A lot of the high dollar custom built beanfield type rifles won't shoot that good!
I always have a trigger job done on my rifles before shooting, no matter what, but it isn't mandatory, if the trigger seems acceptable, you can have that done later. One thing I would do, before shooting, is check to make sure all the screws are tight on the scope mounts, I've heard of the mounts being loose on these type of package deals. Also be sure the guard screws are tight.
Interesting to hear how your rifle was very dirty. The dirtiest new firearm I ever purchased, was a brand new Colt Gold Cup stainless steel. I think it was the very first SS Gold Cup in the state. That gun was absolutely filthy. I went back to the that dealer and ripped his a$$ but good. He swore up and down that they hadn't taken my new gun out to the range and shot the heck out of it before I bought it! Actually, most, if not all, new guns are test fired at the factory, so there really is no such thing as an unfired NIB gun. Some, however, are apparently shot quite a bit at the factory, before they are shipped. I always clean the bore on any firearm before shooting it, and grease the back of the locking lugs and the cocking cam. Good luck!