Loren,

The number you cite is an annotation made during your grandfather's naturalization process.  Specifically, it was done during the verification step, where a Certificate of Arrival was issued.  The number before the hyphen ("2") is the district number: in this case, New York.  The digits following the hyphen are the Certificate of Arrival number.  Unfortunately, there is no index for these numbers.  The date is when the verification took place. I have seen this anywhere from a year, up to a couple of weeks, before the Petition for Naturalization (and, in one odd case, even a couple of weeks afterward), with most about one month before the Petition.

So, in your case, I'd search for a naturalization petition for your grandfather in New York around November, 1930 (31).

For more info on these and other passenger list markings, see the InfoFile on JewishGen:  https://www.jewishgen.org/InfoFiles/Manifests/occ/

Regards,
David Oseas

Researching:
HYMAN/HEYMAN/HEIMOWITS/CHAJMOVITS: Zemplen-Dobra, Hungary > New York
KLEIN: Satoraljaujhely (Ujhely), Hungary > New York > Los Angeles
KRONOWITH: Hungary > New York
OSEAS/OSIAS/OSIASI/OZIAS: Iasi, Romania > Chicago > Milwaukee > Los Angeles
SCHECHTER/SHEKTER: Kishinev, Bessarabia > New York  
SHERMAN: Iasi, Romania > New York > Los Angeles
STRUL:  Iasi, Romania > Haifa, Israel
WICHMAN: Syczkowo (Bobruisk), Belarus > Milwaukee > Los Angeles