Magento CE 1.7.0.2 – Manage Number of Address Lines in Checkout

Yes,it possible

At class of Magento\Checkout\Block\Checkout\AttributeMerger in function getDefaultValue($attributeCode) ,

and below code:

case 'telephone':
                /* add by Amit Bera */
                if ($this->getCustomer()) {
                    return $this->getCustomer()->getYourCustomfield();
                }
                break;

Edited:

You done the mistake,you need to assign that field checkout and other form where you need it

 $used_in_forms[]="adminhtml_customer";
        $used_in_forms[]="checkout_register";
        $used_in_forms[]="customer_account_create";
        $used_in_forms[]="customer_account_edit";
        $used_in_forms[]="adminhtml_checkout";
        $attribute->setData("used_in_forms", $used_in_forms)
            ->setData("is_used_for_customer_segment", true)
            ->setData("is_system", 0)
            ->setData("is_user_defined", 1)
            ->setData("is_visible", 1)
            ->setData("sort_order", 100);

        $attribute->save();

The solution for me needed an option changing in admin. An option that was different from the system my data was migrated from... weird.

Configuration > General > State Options - make sure UK is NOT selected. I also found a SQL insert statement that can add all the UK "states" (Counties etc) to the database, which I guess would then allow the option I deselected to be selected, thus enforcing that on UK users, and ensuring the end user cannot make a typo when entering that part of their address (it would be a select list to choose a "state" from).

Anyway, this seems to have fixed my issue, so hope this helps anyone encountering the same issue!