I thought I would share what I have learned recently in trying to secure an original rebuilt carb off the interweb.  I have an original  Holley ECZ  AD, List 1273 carb on my '57 Tbird, that was in need of updating due to worn parts.  I found a nice-looking original one from a reputable rebuilder on eBay. It arrived with the incorrect metering blocks, air bleeds, no float bowl vent,  and would not run on the car. 
To add insult to injury, a nationally known rebuilder that lives nearby informed me that the eBay product had been re-stamped on the air horn, and was a forgery.   He said he had been seeing an increasing number of forged carbs on hard-to-find and valuable models, especially from vintage Corvettes.   I guess that practice has now entered the Thunderbird community.   
So, as they used to say on Hill Street Blues, be careful out there. 
 I will try to post some photos from a different appliance.   
Ralph