I would strongly recommend that you buy Suppliers to the Confederacy -- both Vol. I and II as you will find some very interesting information in Vol. I about Joseph Wilson -- the maker of your rifle. Makers often stamped their name on the belly of the stock as yours is stamped since many used locks made by other firms whose lock plates are simply marked TOWER and the date. Joseph Wilson of 67-70 Great Charles Street, Birmingham was one of the most important gun makers of the era. One of the two authors of the two volumes I recommended is Craig Barry, a frequent and very knowledgeable contributor to this site. These two volumes are readily available and can be found on Ebay.
If you want to see who made the lock on your rifle, you need a hollow ground screw driver that fits the two lock plate screws so that you don't bugger up the metal slots in the screws. Hollow ground screw drivers have the tip ground flat on each side so that both sides are parallel. Normal screw drivers have a carrot shape tapered at the point and this slips around in the screw slots and causes the metal to disfigure. Many lock plates are stamped with the maker on the inside above the main spring. I use a set of different sized hollow ground screw drivers I ground the tips on myself from regular screw drivers and I always put a small piece of scotch tape on the tip so that there is a very tight fit and no metal to metal contact that removes patina as you turn the screw driver. Messed up screw heads are the bane of collectors!