With the AKM parts I have learned what markings are on good parts and what markings indicate a counterfeit part. That's not 100%, but good enough to at least eliminate the large majority of counterfeits. I have wired $40,000 to a vendor who supplied me with 10 parts that have been tested. This is mediated by Alibaba, so in theory I would be able to return the parts and get a refund if they are not good.
With the ADI part, things aren't so simple. The AKM part has a date code and they will validated specific date codes if sent to them. ADI won't divulge their marking format or any details. They also won't provide an indication of valid or invalid markings if photos are sent to them. So I can't say for sure that any parts are counterfeit by looking at images. Every part I have handled in the 13 years I've been buying them was the same, the part number split onto three lines with the middle line containing the ADI logo and an embossed pin one mark. Some 90% of the parts I find on the web put the part number on two lines with a pound sign and three digits on the third line, usually with a laser etched pine 1 mark. I'm pretty sure these are counterfeit, but I can't be sure if ADI won't confirm their format in any way. ADI did say a pound sign is used in part numbers (in general) to indicate lead free, but they won't say if this part uses that or not. Every part I have is lead free, but no pound signs.
One distributor who seems to be other than an Alibaba phantom is chip1cloud.com. They have emailed me that they have a number of the ADG1411YRUZ for a reasonable price. But they want payment in advance and don't seem to be talking about an escrow agent. I can't find anything on the web to indicate they are a scam operation. Anyone heard of them or used them?