all amps created equal?

[mojuc]

I just recived my new cycle. I was looking at the amps Testex Cyp. 250 and the tops of the amps the part you snap off, some of the amps are a little taller and wider than others just the nipple part of the amp. There is not a huge difference in size but it is noticable on a couple of them.Just wondering if this is normal cause the deca amps I recived the neck of the amps are all the same size.