Most brackets in the engine compartment were made in the Chrysler plants and dip painted in a cheap glossy enamel that faded to what many would call semi gloss. These can be identified by the paint runs that always happened after dip painting.
There is a detailed explanation of dip painting in the book "How to Restore Your Muscle Car" by Donahue, 2nd edition, 2005. Basically a water filled vat is topped with a thin layer of oil base enamel that floats on top, Parts are dipped, then hung up to dry. This method was used by all auto makers in the 60s-70s because it was much easier than spray painting and wasted no paint by overspray. This method works very well with big bulky parts like seat frames/springs.
You can dip paint using a bucket or similar filled with water and topped with 1/8" or so of Rustoleum black enamel, pint size, from WalMart, using wire hooks. The bucket must be large enough and deep enough that the parts never touch any side or bottom, or the paint film will be disturbed.
Some examples are brackets for A/C, alternator, and PS; receiver dryer bracket; motor mount brackets; horn brackets; clutch torque tube; removable transmission cross member; etc.
Components provided by vendors, such as the A/C compressor and the receiver dryer were typically spray painted by others in a semi gloss black.
