Ususlly you can find proprety records online. I founf this site whic appears to alloow you to search property records. Looks line you would b better off searching with the block and lot number. Hopefully the records show how the home is "zoned", meaning if it's a legal 2-3 family home.
When in doubt, call the country clerks office, who can direct you to the proper web site of person to verify what you are seeking.