pos/pos_restricted_customer_list/views/res_partner.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2017-2019 Therp BV <https://therp.nl>
     License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl). -->

<odoo>

    <!--FORM view-->
    <record id="view_partner_form" model="ir.ui.view">
        <field name="name">view.partner.form (in pos_restricted_customer_list)</field>
        <field name="model">res.partner</field>
        <field name="inherit_id" ref="point_of_sale.view_partner_property_form"/>
        <field name="arch" type="xml">
            <field name="barcode" position="before">
                <field name="available_in_pos"/>
            </field>
        </field>
    </record>

</odoo>