When Boromir was not travelling with the fellowship, would he have used a different shield. Can it be said that his round shield seen the the films was a "travel shield"? When he was fighting at Osgiliath, for instance, he would have used the same shield as is used by the generic warriors of Minas Tirith?

It is seen that he wears similar heavy armor like the common warriors wear although his is much more ornate so would he have used a similar shield as well? Is it common for a soldier to bear the same shield in all cases like a sword?