at all positions. The players choose which ones they participate in, the scouts and GM's and coaches pay attention to specific drills for each position along with the positional drills at the combine. Kickers also particpate in the 40 yard dashes and bench press and vertical jump and so on. But do you think any scout cares what a kicker does in those drills? Not a chance.
Scouts will look at the 10 yard dash of an OL, and maybe even the 20, but the 40 is meaningless to them for an OL.