i just picked up a nib g20. i have not fired it yet, but when u remove the slide, sometimes the quide rod falls out, and when it doesn't fall out, its no longer seated 100%. it goes back into place and seems tight, but after racking the slide then remove again, its moved. i did remove some oil from the area, and it seems to just move downward a little now, is this ok? the slide moves just fine.