There is no doubt in my mind that the full radius horns without mesh will flow better than the original on the flowbench. Whether the engine will put out more horsepower with them, especially with an original style cold air box remains to be seen.Most of us have abandoned the curved velocity stacks in favor of the newer "mushroom" horns... flow bench test show these to be better.
Pegasus -Air Horn, 45 & 47mm General Purpose - 40mm Tall
Replica curved airhorns look like the are likely to flow better than the originals but they won't fit the box w/o modification - a lot of 1600's in European Historic racing are in fact using these with the screens removed w/o airbox.
Generally 105 type engines seems to respond well to a lengthening of the intake tract. Also, the straight horns put the bellmouth very close to the outer wall of the airbox which may interfere w/ flow.
Running short stacks (non-full radius) w/o airbox definitely reduces the torque low down noticeably - didn't drive the car enough with them to ascertain the top powerband. Anyway, I've had good results on the dyno w/ the original curved stacks and airbox on a 1600 twinplug.
Also, I wonder whether slip fit vs. non slip-fit horns give better overall flow. Slip-fit will reduce the barrel diameter of the carb somewhat, but the ridge created by the auxiliary venturi is essentially completely smoothed, thus reducing turbulence in that area of the carb.