Any experts on RMA badges out there - 3

[Ray6930]

RMA cap badge 1922 - 23. Three examples in attached pic. Bottom two look wrong to me - appears cheap, shiny, metal and rear is solid behind the grenade and generally not well finished. The top one may be more chance of authentic as the rear is a bit more detailed and not so rough a finish, with grenade not being solid. The metal is still odd in that is seems thin and 'tinny' rather than hard, solid brass. Anyone have any ideas on what might point the way on these? -- Ray