i'm on 330/340, perhaps the flapless checklist looks more or less the same.
Select Green Dot speed for the initial approach. (say 220 knots)
In a flapless config, we're still required as per the C/L to select CONF 1 (VFE 205 knots). VAPP target speed is limited to VFE-5 (200 knots). So, there is no need to select managed speed as the FMGS won't give you a faster VAPP target.
this is my thought. correct me if i'm wrong guys~
what about if we have to carry out an overweight landing? i guess we can use managed speed to take advantage of GS mini in this scenario. it's not mentioned in the QRH though whether the approach is to be flown at selected or managed speed.