Yes. but you would be using diamond bolts with an addy crossbow, and probably would need 25 super restores (4) versus the standard 16; you'll be using purple sweets to heal and hope you don't run out of hp in any of the waves.
Back then in the old days before the update (when everything spawned in one spot and you could stall pray by opening up a quest guide), it was possible to do it with just 50 ranged with rune arrows. Ide imagine you could do it with 45 or so with diamond bolts (since crossbow hits harder and more accurately, and diamond bolt spec guarantees hits sometimes).
Woah, Well done man! I can't even get a fire cape on a lvl 80 Ranged and 99 Prayer character...lol I'll probably ask Skele_Master to do mine in the future! Cause I want oneeeeee!!