You might as well take off the cover. The bolts don't have sealer on them so can fall out onto the gears, and that can be worse than the dowel pin because they have flanged heads that can catch in the teeth. Remove, clean, loctite the 4 you can get, and bend a 10mm wrench to tighten the fifth that is under the cam gear and not visible through the "windows" in the gear. Check the cam retainer and oil pump bolts.