Canon Extension Tube has S/N?

[eli452]

I have received the 2 Canon extension tubes EF12II & EF25II. The only writing on the tubes was "1301" on the EF25II and "1201" on the EF12II. So my question are these S/N?
On the box there are several more writings, for the EF25II:
CZ 23522000DB0107
9199A001 [AA]
EAN/JAN 4 960999 204307
UPC 0 13803 03560 5
Searching the web EAN is probably Electronic Article Number, JAN is Japanese Article Number and UPC is Uniform Part Code.
no "1301" in any of the above.

 

[7enderbender]

I have received the 2 Canon extension tubes EF12II & EF25II. The only writing on the tubes was "1301" on the EF25II and "1201" on the EF12II. So my question are these S/N?
On the box there are several more writings, for the EF25II:
CZ 23522000DB0107
9199A001 [AA]
EAN/JAN 4 960999 204307
UPC 0 13803 03560 5
Searching the web EAN is probably Electronic Article Number, JAN is Japanese Article Number and UPC is Uniform Part Code.
no "1301" in any of the above.

As far as I remember: no they don't have serial numbers. I had the same question when I bought mine.

 

[Loswr]

They're not long enough to be unique serial numbers. But there are different numbers on my EF 25 II (left) and EF 12 II extenders than on yours, so I suspect they are production codes of some kind.