HK020/HK030 are modern style knobs -- neither the plastics or the paints are '50s specs.
In the '50s the knobs were clear CAB butyrate with bright gold paint. So as far as the appearance of '58 knobs when they were brand new, HK020 gold would be reasonably close. (Modern acrylic is crystal clear -- a little clearer than new CAB so not an exact appearance match.)
CAB yellows as it ages, and shrinks/deforms a little. The metal particles in the old gold paint turn green on the exposed bottom surface and change the color of the paint a bit when viewed from the top through the CAB. HK030 amber knobs are a poor attempt at looking like old CAB knobs.
Acrylic doesn't yellow as it ages, and the modern paint is more resistant to greening, so HK020 golds won't age like CAB knobs.
There are "aged" acrylics that look more accurate than HK030. And there are actual CAB repros that will age like the originals.