You get the social security number after the I-765.
I *think* (and may be wrong) that you have to go to your local SSA office and apply for your social security card after you get the GC approved (because it says to bring the green card if you have it).
From the Social Security Agency:
SOCIAL SECURITY NUMBERS FOR U.S. PERMANENT RESIDENTS
We are pleased you intend to immigrate to the United States. Upon admission to the United States based on your immigrant visa, you will be a U.S. permanent resident. Each permanent resident needs a Social Security number to work in the United States, to conduct business with a bank or financial institution, to pay taxes or to be claimed on a tax return, and for other purposes.
If You Requested a Social Security Number When You Applied for Your Visa
If you requested a Social Security number card as part of your visa application and are age 18 or older when you arrive in the United States, the information needed to issue you a card will be shared with us by the U.S. Department of State and the U.S. Department of Homeland Security. You do not need to fill out a special application or go to a Social Security office. We will assign you a number and mail your Social Security card to the U.S. mailing address where the Department of Homeland Security will send your Permanent Resident card. You should receive your Social Security card within 3 weeks after you arrive. If you do not receive it, call us. If you change your mailing address after arriving and before you receive your Social Security card, call us. We will provide the Department of Homeland Security and the Department of State with the number we assign you.
If You Did Not Request a Social Security Number on Your Visa Application or are Under 18
If you did not request a Social Security number card as part of your visa application or are under age 18 when you arrive in the United States, you must apply for a card at a Social Security office. When you have a permanent address where we can mail your card, please call us to find out where to apply.
When you visit a Social Security office to apply for a Social Security card, take your passport or travel document, Permanent Resident Card (Form I-551), if you have received it, and a birth certificate for each family member applying for a number. A Social Security representative will help you complete the application. You should receive your card about 2 weeks after we have everything we need to process your application. If we need to verify any document with the issuing agency, it may take longer.
Additional Information
We do not charge a fee to assign a Social Security number or issue a Social Security card. If you should lose the card, we will replace it for free. We suggest you keep your card in a safe place, as you would any important document.
We keep strictly confidential all information you provide for a Social Security number and do not disclose it except as provided for under the law. For example, we may share information with other government agencies as permitted under the Privacy Act. For more information about this, please contact us.
In the United States, you may call the telephone number listed for the Social Security office in the local telephone directory under “United States Government” or Social Security’s toll-free number, 1-800-772-1213. You may also locate the nearest Social Security office on the Internet at
www.socialsecurity.gov. If you need to contact us before you leave for the United States, we are assisted outside the United States by United States embassies and consulates throughout the world. In the Philippines, the Veteran’s Affairs Regional Office in Manila assists us.
I am interested to hear of I am wrong because getting my ssn is one of the things I want to do as soon as possible to start generating a credit score and report of my own (it takes 6 months, which is when we're hoping to buy a house).