Although the penal code does not specify this, it is common practice. Restrictions are not mentioned in the penal code either, and they have been upheld in court as ok.
That is correct, and sometimes bureaucrats do the same thing. I found a case from 2003 (Bach v. Pataki)in which a non-resident sued New York state in federal court because he was told, in writing, by the division of criminal Justice that the state would not issue a handgun permit to a non-resident (despite his stellar credentials.)
He did not challenge the DCJ's decision on the basis of state law. It would have been interesting to see if the New York courts agreed that the law does not allow issuance of permits to non-residents. Instead, he challenged it on federal constitutional grounds. The court first addressed whether the second amendment provided a collective right or an individual right. It held that the 2nd did not provide an individual right and therefore the state's refusal was to be reviewed on the "rational basis" test rather than the more stringent "strict scrutiny under the Equal Protection Clause."
The court went on to find that NY's refusal to license non-residents passed the rational basis test.
If the SCOUTS holds that the 2nd applies to the states, then under Heller, a case like Bach might be decided differently because the court may be compelled to apply the strict scrutiny test.
Outside of the courts, there is a bill pending in New York to filter all non-resident applications through Albany County - the bills sponsor apparently believes, unlike the DCJ, that NY law does allow for the issuance of permits to non-residents, but that the process for obtaining one is not clear. Here is the bill sponsor's statement in support of the bill:
Although non-residents of New York State are not precluded from being licensed to possess a gun in New York State, the process is hampered in part by language that encourages a permit applicant to make such application in the county where he/she is a resident.
Furthermore, there is no central registry for out-of-state license holders allowing for inconsistent registry information depending upon the county that processed the application.
This legislation provides a consistent process with a central application office, yet still insures responsible gun possession by requiring that the applicant hold a valid firearm license from their home state as well as subjecting him/her to a new background check.
So maybe change is coming.