Can you still become a vampire lord if you have killed Harkon and cured Serana? [duplicate]

Can you still become a vampire lord if you have killed Harkon and cured Serana on Xbox 360? I tried to talk to Serana before I cured her but the option did not come up.

A short lookup gave me the following advices:

In order to gain this ability, you must accept Lord Harkon's gift during the Bloodline quest or receive it from Serana after Chasing Echoes.

From here

and

Harkon or Serana can grant this power during the main questline for Dawnguard. Harkon offers this power during "Bloodline", Serana offering it twice, once during "Chasing Echoes" and once upon completing "Kindred Judgment.

From here

By "this ability" or "this power", becoming a vampire lord is meant.

Also Serana's mother Valerica can grant it after Serana's is cured by visiting her in the soul cairn ( after you tell her she's freed she will be on the balcony of Volkihar castle), however you need to be a vampire lord to re-enter the soul cairn.