I knew that the SN in scoop's filecard was: 887-1192-XE86 but i just got a card that has totally different number. Were you guys aware of this variant? How rare is it?

Yes. There are a few from '88 and '89 with SN variations:
http://www.yojoe.com/action/variations/varfile.shtml

So would this be intentional variations.. like when they say the SN has been modified to prevent breaches in joe security.. or are we talking a total typo error or mix up with numbers by accident?
N3M