some consignment stores authenticate in person by hand but they wont provide a proof of authentication

it's really a case by case basis from what others have told me on the H discussion forums, you'll have to ask around. i had the H buckle purchased from the store (2011/2012) and i saw one on eBay for $150 from a seller and it looked exactly like mines, even the matte texture on the back and the hermes stamp was so finely etched that it looks believable.. the only way i knew it was fake was because the seller was selling 10 of the exact same belt buckle, and all his feedback was 100% (possibly from ppl not knowing they aren't real) for the belt buckles. that's why it's almost impossible to get an authentication anywhere. i believe i was told the superfakes (coming from bulgaria) are easy to manufacture since they're molded from a molten metal and then machine polished with a rotating rubber belt, finally they are electroplated with gold or palladium. similar to how Hermes makes them. the whole process is machine made when it comes to metals, thus the influx of superfakes
i attached some pictures of the superfakes coming from bulgaria (note this is the older style of the belt buckle they are replicating) .. the new ones have serial numbers now (to reduce the number of superfakes) but back then Hermes did not use number marking. this person on eBay is selling 10 Hermes buckles right now and all his feedback is from ppl purchasing the belt buckles. either it's a superfake (likely) or he works for hermes (which i doubt because there's no way he could be selling so many of these belt buckles without H knowing and also Hermes has used number marking on the constance H belt buckles for more than 5 years now, they aren't making the H belt buckles like these anymore) -- please correct me if i'm wrong, but this is based on buying belt buckles from hermes since 2011 and also based on back dated posts from other members on this thread, you can search back to see pictures