Looks like good start for the collection a decent shape S84/98 looks like correct blueing on blade, WaA243 most probably on parts, the frog looks correct for the period.Mundlos Magdeburg 1938 production.It should be oiled on parts, that will not rusted more on surface.There are some good books George Wheeler, Seitengewehr 1918-45, some good sites in Inet, k98.free.fr