I've used the 135mm Rodagon for 4X5, and it works well. From what you say, a condenser problem is certainly possible, as discussed above. You also need to be aware that the turret places the lens further away from the negative and creates a little tunnel between the lens board and the rear element. Since 135mm is somewhat wide angle, this may be the problem if the condenser alignment doesn't cure the vignetting.
They have a bunch of different stuff left over from when the darkroom was actually used.
If the turret creates a problem, I'll just swap it for a plain lens board.