JeffCo Property Records: https://propertysearch.jeffco.us/propertyrecordssearch/address/property/details/hs83lnTgq8v9ENcjzu6DDcuaaYl51wkr5NSb7DGGfpU1

show it was built in 1932, with 543 sq-ft first floor and 543 sq-ft finished basement. Levels below ground don't count as levels on OSM unless they are partially above ground. Maybe the basement is partially exposed?