These are Roof Rail Weatherstrip Channels. The long section goes along the top of the roof while the shorter section runs up the rood pillar. The two sections are joined by the small elbow piece. Together they form a continuous channel for the soft rubber window seal to be retained. The window glass will seal up against the seal in this channel.
roofrailchannlesJohn Margozzi (margozzi), from
'69 Grand Prix