The difference in composition between 316 and 316L stainless steel is that 316L has lower carbon content (< 0.03%). The lower carbon content is only important to corrosion resistance if welding is involved. Because of the higher carbon levels, welding 316 can lead to sensitization and precipitation of chromium carbide at the grain boundaries making it more susceptible to intergranular corrosion. If 316L bolts are working satisfactorily in your environment now, 316 bolts should work too.