so unless the checklist says no spoilers or they are inop I'd have thought them very useful.
But why? The ground spoilers put the weight on the wheels so that the brakes are most effective. This had no wheels or brakes therefore there use is surely largely reduced and possibly negligeble though every little helps. I wouldn't have thought it a make or break decision.
Increasing the weight on the tarmac/metal interface has the same effect as a tarmac/rubber interface in terms iof increasing friction.
(Note, I make no comment on spoiler use. I have no idea of the proportion of runway used, what the qrh says etc. But most assuredly the basic physics is comparable.)