[old_tv_nut]

"the chroma amplifier circuit should peak a little above 4.1mc"
True, and I would expect to see that if you look at the 2nd amp cathode with the color level set to max. However, I would then still expect to see L18 tuned to 3,58 MHz so that the whole sloped response goes up and down with the color level control.

Note that this means that you would still expect to see a sloped response at the final test point (cathode of the R-Y Demod) because the injected 3.58 sweep has not been RF modulated and passed through the IF. So this makes the illustrations of final flat response suspect.