The mods get the Chorus to flanger-ish when the Roto-Tone is turned but when it’s turned back is no effect on chorus function.
This one has the Roto-Tone Wilkie1 capacitor mod and the earlier electrolytic cap on a switch mod which (if I understand the mod correctly) adds a 10uf cap to the 2.2uf cap – when the switch is flipped on it gets even more flanger-ish than the Wilkie1 mod but still not a purpose built full on flanger. When off it also has no effect on the chorus function.

This is what I worked from in the first run before the Roto-Tone and Wilkie1 mod:

With the Roto-Tone you can ignore the pf caps on the left side of the switch.
Chuck
Chuck