How to test if your bars are real without drilling into them?
Assuming weight and dimension are on point and they pass the acid test because they have actual gold coating, how could one test them?
you get them from a reputable source, if you get a dud you're fucked anyway, it's not like you're going to get a refund. you should never have to seriously consider "what if my bars aren't real?" in the first place.
no, unless you have a friend who is an analytical chemist and is allowed to test any old shit in his lab then there's nothing you can personally do to ensure your gold bar is genuine gold and not a good fake, other than getting it professionally tested.