...yes you can. last i heard, the only entries you can't read that were made before your character showed up are the lucetilocked posts because they use a different network than the normal ones. everything else is fair game. otherwise, how would people find the guide on their own? it'd have to be reposted literally daily otherwise.

and it wouldn't make sense to be unable to access older entries unless someone else links them. they'd either have to be completely inaccessible to people who arrived after the post or accessible to anyone at any time unless they're locked.