Re: New to this...
There were a few models recalled about 10 to 14 years ago.
Yes the oil needs to be scrubbed out. Century Arms has sold some nice stuff and some junk. Keep your loads moderate 70 to 90 grains is enough for deer anyway.
If you shoot pellets, keep in mind that most substitutess generate higher pressures than black and sometimes 20% more, so back off on your load if using them. I would reccommend avoiding Pyrodex simply because it is more corrosive than black powder and even harder to scrub out.
There's nothing wrong with black powder, and it is cheaper than using pellets. I'd stick with 2fg. You didn't mention the rifling twist. A few older in-lines were indeed intended for patched round balls.
I once worked in a sporting goods store (1970's) and we sold Century Arms products. Back then as I recall, one of their products, a smooth bore flintlock, was recalled. Most of their stuff was fair to nice.
See if you can get another black powder shooter to meet you and give you some tips as you go through the process of cleaning and loading at the range. Whatever, you do, stay within the load reccommendations of the manufacturer. Some guns will take all kinds of abusive loads, some won't take any and with disastrous affect.
The NMLRA web site has some instructional guides avaailable on line, I think under publications.