Yes that is a weld spot near the bung, it was there when they were new. 1628 is the JBA part number and yes D-216-28 is what is on the tagI notice in the pic with the EGR bung where it attaches to the main tube it looks like there is a welded spot or is that some gunk build up or what???
Also is that number in the 2nd pic D-216-28???