Your belt buckle is definitely a modern-made (late-1900s/early-2000s) crude imitation of an early-1800s American Military "tongue-&-wreath" 2-piece buckle. But it is not a Reproduction of any actual early-1800s military buckle, because none from that era said "Suburbia Americanus" on them. Buckle collectors call the type of buckle you found a Fantasy buckle, because although it is manufactured to look like something from a past era of history, no exact match for it existed during that period of history. An example of a Fantasy buckle is the CSA "Confederate" belt buckle worn by actor Nick Adams in the TV-series "The Rebel." No exact match for it existed in 1861-1865... it was dreamed up by the show's Prop Department. There are many other examples of Fantasy buckles worn by actors in movies.
One clue that it is a modern-made buckle is the words "town belt" on the back of your buckle's wreath section.
The phrase on your buckle, "Suburbia Americanus" is a slang adaptation of the use of Latin phrases for naming Biological species... for example, Homarus Americanus is the Latin name of the American lobster. The literal translation of "Suburbia Americanus" means an American who lives in a major city's suburbs. Do a google-search for the phrase "Suburbia Americanus."