Remington has offered shotguns in 16 gauge off an on over the years.
The Model 870 16 gauge with a fixed choke barrel was offered prior to 1962. In 2002, it was brought back into production with a Rem Choke barrel. The Model 870 Wingmaster in 16 gauge was produced from 2002-2006 and the Model 870 Express was produced from 2002-2005.
This newer version came with the following specifications:
Bore diameter: .670
Improved Cylinder choke: .661
Modified choke: .653
Full choke tube: .636