I locked them all out, but didn't hold them there. I have thought about doing a more definitive, ~half second hold at lockout but haven't done so yet. I don't really have any lockout problems with my pulls; generally, if I can get it past the first few inches off the ground, I can finish it. So it's not a weak point, and since my hook grip is significantly weaker than my alternate grip, not holding the extra half second allows me to use the hook for all 5 reps.
If lockout gets to be a problem, I may change this, but since I do rack pulls regularly with an alternate grip (and will strap once I need to), with a full definitive lockout, I think doing my regular pulling like this is fine.
Note Jordan doing the same weight (515x5) back in June does the same thing, though he did hold the last one for that extra half second.