Bookworm is right, higher weight results in higher speed for maximum L/D and therefor in higher reynolds number. For high performance gliders this means about 0.5% better L/D a t maximum weight.
On the other hand we talk about large transports, and there is another number getting important : the mach number. Especially at high altitudes the speed for best L/D is at a mach number above .5 and this results in increasing sonic drag with increasing mach number. Best L/D corresponds with quite large CL so highest local mach number on the wing´s upper surface might be twice the nominal mach number, so supersonic flow might exist at best L/D AOA and speed, if altitude is high.
But all these influences are marginal in comparison with the errors hidden in the ´rule of thumb´ values for optimum speed which is used by the pilot. So even a very good pilot will waste a few percent in glide ratio because he lacks the neccesary informations.