Experts may have a more specific answer for your particular situation, as it can get extremely technical, plus NEC version can make a difference, as well as local and/or utility rules. (Listing your city/state and electric utility may be relevant here.)
But the basic concept is (has not always been this way): Neutral grounded to bond in exactly one location. This meter box comes with the bond in place - i.e., neutral bonded to ground. If the service is "not grounded" that means "it is grounded someplace else, so don't ground it here" --> "remove the bond (the metal strap under the red label, currently held down by the screw). If the service is supposed to be grounded, leave it as is (the red label is not blocking the neutral ground bond).
But if the service is to be grounded then you would remove the neutral ground bond from your main panel (so that it is only bonded in one place) and you would need to separate grounds (to only be on ground bars) from neutrals, and there may be an issue (I truly don't know) of where the ground wire to the ground rods terminates. Speaking of which...
The ground wire to the ground rods should be solid, not stranded. This may be a local thing. Based on NEC 250.62 it can be solid or stranded.
- The ground wire should be continuous - i.e., one wire that goes from the panel to one ground rod with a proper clamp and then to the second ground rod - no breaks/splices along the way, except with certain special types of splices (not your usual wire nuts).
And most definitely:
My current inclination is to leave the bonding strap in place (but remove the label as it seems to be partially insulating the screw from the strap)
Do NOT do that. The screw is providing pressure the metal bonding strap to hold its nice big surface area against the surface area of the box, plus the screw threads are connecting both. Whether the washer actually contacts the surface of the bonding strap is irrelevant. But removing an important label is never a good idea - airplane accidents and other serious things have happened because labels were removed.