Native English speaker. I tried saying both out loud and it sounds the same. It's just a glottal stop (?) either way in my accent.
They should sound different. Not a lot different, but there is normally a noticeable difference between g and c sounds.
"Hard c" is voiced, "g" is unvoiced.
They should sound different. Not a lot different, but there is normally a noticeable difference between g and c sounds.