R. Marshall,
I have a few and some things to look at are that the gun is on face and there is no play with the forend off. Same thing you look for on a SXS. I usually put in some dummy rounds with painters tape over the backs and make sure I get good firing pin strikes on all barrels and do it a couple of times to make sure the selector works correctly. Also if the barrel selector raises the rear sight make sure that it also lowers it. Check there are no cracks in the stock or forend and finally that the barrel & ribs are tight.
I like to slug the rifle barrel to make sure I have the right size bullets, also check the chamber length, more likely that not it will be 65mm (use 2 1/2" RST or something similar).
As others have suggested more pics are needed. From what I see the area in the picture showing the maker the solder joint between the rib and barrel looks a bit funny, it appears to be an unusual build up of solder or maybe just oil or grease? I would look this over very carefully to make sure it is not "repair" of some sort.
Other than that start looking for some 8X57 JR ammo and have fun.
WBLDon
