I think you mean carriage bolts, not stove bolts. I had to change sides with my original Ludwig "side" tom mount because I'm a lefty, they plugged the holes with carriage bolts...they have that little "square" under the round head so they don't turn.Plus 1 on that.Extra holes are very common, on drums this old. People did all kinds of "mods", to get things positioned better. I once saw an old Tommy Aldridge (Black Oak era) Ludwig double bass kit that had a slew of Rogers swiv-o-matic mounts on his kicks.A common "old school" fix, is simply put stove bolts into the holes. Some people think that looks better than the empty hole.A more complicated fix, is to glue dowel plugs into the holes, and then glue matching wrap pieces (cut round and correctly sized) onto the plug.Of course, if you don't mind the holes, you can just leave 'em be.