I know a pass rush is more than sacks AND their passing yards allowed number is low because most Bills' opponents ran successfully against, but they did have 32 sacks, which put them at about the mid point of the league. They also allowed the 2nd fewest yards per game.
Therefore, along with this talk of Spiller, I don't see why they should not be trying to fill their biggest need (OL) in the 1st round.