You are getting the address items from the admin, Order Summary page?
If so, try the following:
In the admin /sources/orders.index.inc.php:
Near line 419, find:
$overview_summary['country'] = is_numeric($overview_summary['country']) ? getCountryFormat($overview_summary['country'], 'numcode', 'name') : $overview_summary['country'];
After that, add:
$overview_summary['state_abbrev_d'] = is_numeric($overview_summary['state_d']) ? getStateFormat($overview_summary['state_d'], 'id', 'abbrev') : $overview_summary['state_d'];
$overview_summary['state_abbrev'] = is_numeric($overview_summary['state']) ? getStateFormat($overview_summary['state'], 'id', 'abbrev') : $overview_summary['state'];
In the admin template orders.index.php:
Near lines 163-164, from:
{$OVERVIEW_SUMMARY.town_d|upper}<br>
{if !empty($OVERVIEW_SUMMARY.state_d)}{$OVERVIEW_SUMMARY.state_d|upper}, {/if}{$OVERVIEW_SUMMARY.postcode_d}<br>
To:
{$OVERVIEW_SUMMARY.town_d|upper}
{if !empty($OVERVIEW_SUMMARY.state_abbrev_d)}{$OVERVIEW_SUMMARY.state_abbrev_d|upper}, {/if}{$OVERVIEW_SUMMARY.postcode_d}<br>
Near lines 174-175, from:
{$OVERVIEW_SUMMARY.town|upper}<br>
{if !empty($OVERVIEW_SUMMARY.state)}{$OVERVIEW_SUMMARY.state|upper}, {/if}{$OVERVIEW_SUMMARY.postcode}<br>
To:
{$OVERVIEW_SUMMARY.town|upper}
{if !empty($OVERVIEW_SUMMARY.state_abbrev)}{$OVERVIEW_SUMMARY.state_abbrev|upper}, {/if}{$OVERVIEW_SUMMARY.postcode}<br>