Keep in mind that some cities don't have any rules regarding pins. Search the site linked above and if you don't find anything, check the city's website using the same search terms. If you still don't find anything, a visit to city hall may be in order. Generally speaking, the farther east you live, the more likely a license and/ or permits are required.
If there are any other pins on location in town, you could politely ask the owner of the business what was required. Good luck!