Spark plugs

[Rnash2002]

Ok bought a set from a ebay seller but im not 100% sure if they are genuine, just seem to look different where the numbers have been stamped, the germany seems different.
I had a flat spot of sorts at about 2k rpm and once i had changed to the new plugs it went but then returned a day later.
The 3 numbers are different at the end of the germany and the volvo stamp in white is bigger on one also.