I am sure the black & white only added to the somber effect of the JFK procession...
You're probably correct -- even if it were broadcast in color, the television I was watching was B&W, with rabbit ears, and tinfoil on them LOL.
Now, after decades of being used to watching color TV, and over the years as the sets and broadcasts have improved, comparing today's procession to JFK's would be almost like comparing a digital capture from C-SPAN posted on FR, to a Matthew Brady photograph.