It varies....
On my '66's, upper power steering bracket are all engine color. Not sure on the support bar, but the pumps are always black.
The upper alt bracket is engine color on my 2 Fremont-built cars, and black on my Baltimore-built cars.
My '65 had NO paint on the upper alt bracket! It was built in Baltimore, August 1965. So you have 3 choices for paint (or no paint)!
Lower alt bracket, bare aluminum on all my cars.
Engine mount adapter plates: no paint.
I'd speculate the alt and brackets were installed after the engine was painted. Engines were painted at the Flint facility, and shipped to the various assembly plants where accessories were installed.
Brian, I'll take your comment one step further and say there should be 'some' paint on the fuel pump....basically overspray on the base, but the whole thing wasn't necessarily painted. Again, it will vary depending on which worker painted it.
BTW, all my bellhousings didn't have paint on them. What have you guys observed?