Greetings,
I'll try to help out a bit:
For starters, I think that an unfired M7600 for the price you listed was great. You got a good deal!
I have no idea about the checkering, sorry.
For sights/optics that depends on you and your style of hunting. If you are hunting to where shots are 100 yards or less, then an aperture sight or low powered scope may be what you want. I honestly prefer scopes even for close range work as they are a plus in low light associated with deer movement times and the thick timber. A good quality 4x scope would serve you quite well over a variety of terrain/shot opportunities. However, if this is your go to or primary gun, you may want more options like a variable. I have a Leupold VariX-III 2.5-8 on my M760 and it suits me fine. It has plenty of power for a long shot and at 2.5X gives me good field of view for the close work. It has a 36MM obj. so it doesn't need a "lift kit" to keep it from smacking the barrel and gathers all the light I need. There are several great scopes in 1.5-6, 2-7,3-9 varibable class that would serve you well from shots in your face to across the field. You'll have to decide what fits your needs the best. I chose the scope that I mentioned as it gave me great flexibility without hindering the balance of the rifle a great deal. If your eyes are good, several manufacturers make great aperature sights that easily mount on your rifle. Hope this helps you out some.