People are way way too paranoid about ESD.
In the last 15 years electronics are way less sensitive to ESD.
If you are not doing a bunch of things to induce ESD (like dragging wool socks on carpet), then odds are there was absolutely zero issue.
I only take ESD precautions if I am doing full disassembly and I have NEVER had an electronic device fail due to ESD.
Also touching the shell should have zero effect anyways unless the shell was metal AND the screws actually touched the circuitry.