Raspberry Pi 4 has three models which have 1GB, 2GB, and 4GB of RAM. Is there any difference between these models for powering?
If there is, "The Foundation" has not published any specifications on it. It's clear that there will be some increase in power consumption with more RAM, but from 1 to 4 GB this is almost certainly a small additional load.
Also, "The Foundation's" published figures for power consumption across all models of Raspberry Pi shows only a single figure for RPi 4B: 3.0 Amps at 5 VDC. They ("The Foundation") do not delineate different figures for different RAM configurations. One would ordinarily assume that the published figure of 3.0 Amps would cover the "worst case" power consumption from the 4 GB configuration. Assumptions regarding "The Foundation's" designs and hardware documentation should be made with an extra measure of caution, but in this case it seems safe to assume that a 5V 3A power supply (that meets the USB specifications for line & load regulation) will power the 1 GB, 2 GB and 4 GB configurations.