No, the ISL number is just a number assigned your case by NVC for consular processing purposes.
The immigrant visa number isn't something you need to give them - or ever actually really know or need to know. It is a number USCIS will request from the State Department (which controls Immigrant Visa availability) if/when they decide to approve your I-485.
What you need to give USCIS is the I-130 petition approval notice (a copy) along with a copy of your father's naturalization certificate and an explanation - up front in big letters so they see it - that yours is now a Family 1st preference case because of your father's naturalization rather than a Family 2B case, and therefore a visa number is available.
HOWEVER: speak with a lawyer immediately and BEFORE you file an I-485. Even with an approved I-130 in a current category, an I-485 might not be approved. To be eligible, for one thing, you need to have been maintaining valid immigration status in the U.S. since entry (with very few exceptions). If you have not been maintaining valid status, you can only process abroad - and leaving might subject to to bars to reentry if you have been without status here for certain periods of time and have accrued unlawful presence.
Speak to a lawyer before doing anything!!!
I will agree with my colleague. If you are in United States and overstayed on a valid visa or entered illegally, you might have a problem on the I-485 adjustment of status. Anyway, you cannot file adjustment of status outside the US. Therefore you need to talk to a good lawyer before you make any move.
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