Yes, bulletin is a noun, a singular, common noun.
The word "bulletin" can function as a noun.
The noun 'bulletin' is a common noun, a general word for a quick announcement from an official source about something; a general word for a program or newsletter that a club or organization produces regularly to give information to its members.A proper noun is the name of a specific person, place, or thing. A proper noun for the common noun 'bulletin' is the name (title) of a bulletin.
The plural form of the noun worker is workers.The plural possessive form is workers'.Examples: The workers' schedules are posted on the bulletin board.
The possessive form of the noun month is month's.Example: Each month's schedule is posted on this bulletin board.
bulletin board
The Bulletin ended in 2008.
The Bulletin was created in 1880.
Edmonton Bulletin was created in 1880.
Edmonton Bulletin ended in 1951.
Bulletin of Volcanology was created in 1922.
Philadelphia Bulletin ended in 1982.
Comics Bulletin was created in 2000.