since there are so many unlimited only avatars, many regular members cannot tell if a member has a custom avatar or not.
if you are not sure if a certain avatar is custom, just copy the user id of the member you're uncertain about and paste it in the following url in your browser.
img.cheathappens.com/custom_avatars/user_PASTE USER ID HERE.jpg
What about headers?
img.cheathappens.com/profilepics/ch_PASTE USER ID HERE.jpg