https://web.archive.org/web/20191031233802/https://systemd.io/RANDOM_SEEDS.html indicates that this is not the case. Quote:
When systemd’s PID 1 detects it runs in a virtualized environment providing the virtio-rng interface it will load the necessary kernel modules to make use of it during earliest boot, if possible much earlier than regular kernel module loading done by systemd-udevd.service. This should ensure that in VM environments the entropy pool is quickly filled, even before systemd invokes the first service process as long as the VM environment provides virtualized RNG hardware (and VM environments really should!).