That is correct.
The colorspace drop-down in the write node still needs to be set to ACES - ACES2065-1 (and the rest of the OCIO pipeline correctly set up) or the image data being written must be converted to ACES2065-1 in some other way. Checking the ACES compliant box will not change the image data to ACES2065-1, it will simply flag it as being that, even if in fact it is not.