R16 wheels were offered as an upgrade package or a standard OEM on some trims (or as an option).
my 2002 Solara SLE V6 came with OEM 205/60/16 wheels/tires. other factory setup was 205/65/15 (this I got on my 2000 solara SE i4).
they are both considered as stock.
there is a nice tire size (including plus sizes) calculator for comparing:
there was also another one showing actual pictures of how selected tire would look like on selected rim, but cannot find that now.