it's bonded with glue or a butyl type bonding agent. we first wiped on primer then add a strip of butyl in the stainless and press on,then run through a special (UV) light and cured it. when I worked in that area (chrysler 68-74) and made the sidelights for that year car we used a 2 part glue that worked similar to the late model front Windshield butyl rubber.
