I think it looks VERY NICE in black Nick! And if someday you want to make it look original, the powder coat will serve as a very good base to paint it with Hammerite Enamel. I used the Hammerite gray on my U-Test-M drug store tube tester cabinet. It was easy to use if you have a compressor and spray gun.
I don't see any point in making a fuss about having original paint color on a bench test jig. It's not like you painted a CT100 fire engine red