I wouldn't worry too much about the lack of strip- it is known the later PS2 releases don't have it. In fact, if you look at the other sealed copies of that game currently on Ebay, NONE of them have it.
I would worry about the lack of photos of the seam edges- everyone who knows about sealed games knows you need to check the seams. If he knows enough to know about the strip, he knows he should have put in seam photos.
Of the other listings for that game sealed, two are similar/cheaper priced and have seam photos. The two more expensive listings show some sort of plastic pull-string around the lower third of the box. I'm not familiar enough with PAL or sealed releases to know how significant that is, but you might check those out before commiting to this listing.