Strips such as this are sewn onto the backs of rugs to help them stay flat (as in to not curl up)
There are different materials used but often this is a leather strip (sometimes it is a vinyl strip but not often).
There are several opinions as to why this may be needed.
One is that the serging may have been applied too tight.
Another, and perhaps more common explanation is,
this rug was woven on a loom that may have been just a little bit warped thereby causing uneven tension all across.
I have even heard that this is most often found on rugs from Iran because many of the looms there are very old and the weaver simply has not been financially able to replace it.
It is generally Not seen as a fault nor does this in and of itself make the rug a "second".
Some would say it is a pretty good indication that the rug did indeed come from Iran.
I don't think you will see anything like this on a machine made rug.
As for it being commercially produced......I venture to say that
most of the rugs you will be able to see for sale in this country were made to be sold. That sort of makes them commercial right?
Bottom line is
if you like the rug and think it a fair price
Buy it.
