Expansion tank without lower clip

[80stech]

I just replaced the expansion tank on my wifes X3 M54 and noticed that the "Standard" brand tank does not have the groove for the lower clip. The clip is there as a decoration only. I used the same brand of tank when I did my X5 but didn't notice if the groove was there or not but I do remember thinking that the way the whole thing goes together the clip probably wouldn't be needed so when I installed this one I just assumed they didn't put in the groove to make the tank easier to install since it seems that a lot of people have trouble. Any how it all seems fine and I pressure tested and yanked on it and there was no movement at all but it would have been nice if they stuck a note in the box Anyone else run into this? Cheers