Depends... 275-what? Need the aspect ratio to determine the diameter, and the diameter is the problem with this interference point. But I would tend to agree... he needs more than 3/8 inch of clearance there. 225-60-15s may need a tiny trim, as noted, but his tires look like 275-40-17, maybe?
The slick way to do it would be to take a very shallow tapering wedge out of the outer surface a short distance in from the rollback flange, then bend the flange back to meet it and weld the seam. But it would need to be done artistically to maintain a neat curve to the opening. Might be easier to just cut it away as needed, then weld the flange back onto the edge once you've got the shape right.
@Treblig: I don't think pushing out does anything to fix the problem (unless you pushed it out 3-4 inches, which would be ugly even possible) — it needs to clear the tire at full lock with the suspension loaded and unloaded. The lip needs to be clearanced in the forward direction.