After pulling image from latest 4.7 nightly https://openshift-release-artifacts.apps.ci.l2s4.p1.openshiftapps.com/4.7.0-0.nightly-2021-08-04-165612/release.txt : 
quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:c7ac0fe8c125d9b52bb58f2026c9117b20e8bf2a440b70a4ec4c3db7bb25e8d8  

we still have a mismatch in gcc versions:

# podman run -it 3cdde87861b2 /bin/bash

[root@d47f23757e40 kmods-via-containers]# cat /etc/driver-toolkit-release.json
{ "KERNEL_VERSION": "4.18.0-240.23.2.el8_3.x86_64", "RT_KERNEL_VERSION": "4.18.0-240.23.2.rt7.79.el8_3.x86_64", "RHEL_VERSION": "8.3" }

[root@d47f23757e40 kmods-via-containers]# export INSTALLED_KERNEL=$(rpm -q --qf "%{VERSION}-%{RELEASE}.%{ARCH}"  kernel-core) && GCC_VERSION=$(cat /lib/modules/${INSTALLED_KERNEL}/config | grep -Eo "Compiler: gcc \(GCC\) ([0-9\.]+)" | grep -Eo "([0-9\.]+)")

[root@d47f23757e40 kmods-via-containers]# dnf list installed | grep gcc
gcc.x86_64                                    8.4.1-1.el8                          @rhel-8-appstream-rpms-x86_64           
libgcc.x86_64                                 8.4.1-1.el8                          @System                                 

[root@d47f23757e40 kmods-via-containers]# echo $GCC_VERSION
8.3.1

[root@6260fed49b4b kmods-via-containers]# echo $INSTALLED_KERNEL
4.18.0-240.23.2.el8_3.x86_64

Verified on the latest 4.8 nightly driver-toolkit image from https://openshift-release-artifacts.apps.ci.l2s4.p1.openshiftapps.com/4.8.0-0.nightly-2021-08-05-031749/release.txt

gcc version matches

# podman pull --authfile pull-secret.json quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:a6aef8163dfaa738afbc0c1c585eb1c897b6488d1967081424f41c366b04154c
Trying to pull quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:a6aef8163dfaa738afbc0c1c585eb1c897b6488d1967081424f41c366b04154c...
Getting image source signatures
Copying blob 1cadda38f72d skipped: already exists  
Copying blob a50df8fd88fe skipped: already exists  
Copying blob dc49873df942 done  
Copying blob 9ae8e62eba92 done  
Copying blob 3e8d9fb4b187 done  
Copying config e74aa00154 done  
Writing manifest to image destination
Storing signatures
e74aa0015416db259ea337cd6a8eb02cfd7850620b4217e12abbb47a420fcabf

# podman images | grep e74aa0015416
quay.io/openshift-release-dev/ocp-v4.0-art-dev        <none>                            e74aa0015416  16 hours ago   1.32 GB

# podman run -it e74aa0015416 /bin/bash
[root@38cbe3caec1b kmods-via-containers]# export INSTALLED_KERNEL=$(rpm -q --qf "%{VERSION}-%{RELEASE}.%{ARCH}"  kernel-core) && GCC_VERSION=$(cat /lib/modules/${INSTALLED_KERNEL}/config | grep -Eo "Compiler: gcc \(GCC\) ([0-9\.]+)" | grep -Eo "([0-9\.]+)")
[root@38cbe3caec1b kmods-via-containers]# 
[root@38cbe3caec1b kmods-via-containers]# echo $INSTALLED_KERNEL
4.18.0-305.10.2.el8_4.x86_64
[root@38cbe3caec1b kmods-via-containers]# 
[root@38cbe3caec1b kmods-via-containers]# echo $GCC_VERSION
8.4.1
[root@38cbe3caec1b kmods-via-containers]# 
[root@38cbe3caec1b kmods-via-containers]# dnf list installed | grep gcc
gcc.x86_64                                    8.4.1-1.el8                          @rhel-8-appstream-rpms-x86_64
libgcc.x86_64                                 8.4.1-1.el8                          @System                      
[root@38cbe3caec1b kmods-via-containers]#

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (OpenShift Container Platform 4.8.5 security update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2021:3121