It takes years of knowledge to be able to spot fake tags in some cases, and every year, model ,assembly plant etc. will have certain characteristics that are unique . Their is no way to answer your question,it would take several thousand pages to do so .
My best advice, educate yourself on how to decode, know how each plant and model year tag should be laid out , become familiar with what codes belong on any given tag , and in what order etc.
Sometimes they stand out like a soar thumb , othertimes, not so much .


Greg