Lazy
You can get some little mirrored cylindrical slugs that you can put into the bore and then peek in around the beam of a flashlight. Brownell's catalogue show such things.
If, however a patch slides smoothly down and back up the bore, your bore maybe just fine. I suggest you don't start pushing patches down that bore until you get a good worm (TC stocks them) and maybe a slotted jag (also provided by TC). You'll need a nipple wrench too.
Certainly zillions of deer have been killed with a 45 caliber ball. Your twist is one turn in 48 (probably) so it'll stabolize a round ball, or a maxi ball, which will shoot very hard, and they are definitely enough for a deer hunt.
Those rifles were made to shoot either round or maxi balls. You can buy the maxi balls ready cast. BTW: they are hard to force down the bore. You have to hammer them down with you short starter and then pound them pretty hard with the ram rod.
Ninely grains of 2F or 3F black powder will work fine. It'll kick pretty hard with that maxi ball. Practice with a .440 ball. You can buy them from Speer, or Hornedy. You can use those round pillow ticking patches that TC sells, make sure you lub them, you can buy patch lub too.
In addition to your patches, lub, balls and short started you'll need a powder horn and a powder measure. You can buy one that adjusts from TC (again, or Dixie) or just use an old 45/70 case. The case will throw about 75 grains of black.
After five or six shots I suggest that you run down a wet patch and pull it out. You can wet it in your mouth. Don't reuse those patches, as black powder residue tastes as bad as it smells.
With round balls your gun will be quite comfortable to shoot, but with the maxi ball it'll kick about twice as hard.
If you want a real canon you can jam 130 grains of black down there and stuff in a maxi ball. After you get back up you will understand that a 45 caliber Hawkin with a maxi ball is plenty of rifle for deer, or bear, or even elk.
BTW: You don't need a patch with a maxi ball. So lub them, pushing the stuff into the lub rings before loading one.
Those .45 Hawkins are fun to shoot, as you can load them with maybe 45 grains of black with the round ball and hunt rabbits, then adjust with the maxi ball for big stuff.