I just want to know how to tell whether the audio in the pregap of the first track is included in the rip or not. All the different options make it confusing to me.
It is included in a single-file image rip or a rip with gaps appended to the next track, which I do not advise. Otherwise you extract it manually as a range or index-based. There should be enough terms in the post to aid you in searches for additional information, if needed. I've lost count how many times I've answered this question here.
https://hydrogenaud.io/index.php/topic,49396.msg448865.html#msg448865
https://hydrogenaud.io/index.php/topic,101115.msg836292.html#msg836292