Death Guard as a faction hasn't had Hateful Assault (the CSM version of Shock Assault, giving them +1 attack in effectively the first round of any combat) for long. They got it Psychic Awaking, which was relatively recent. ... That's no longer true as Death Guard have had the rule removed from their Codex.

Did Death Guard lose Death to the false emperor?

This rule was added to Death Guard in War of the Spider and has been replaced with most units just having more attacks. ... Also, Death to the False Emperor is gone, so if you're a Death Guard player you no longer have to worry about remembering that rule.

Do cultists get hateful assault?

Hateful Assault

Units with this rule — basically everything except for Cultists — get +1 Attack in any turn in which they charge, were charged, or heroically intervened.