Here's a Mockba 80 with the skinny lower headlug and the cutout, so you can see there are some similarities with your bike.

http://tinyurl.com/

However, note that the ebay bike has all "flying C's", whereas some of the graphic elements on yours are clearly earlier. That's why my best guess is San Cristobal. If the Mockba 80 postdated the Moscow Olympics as I suspect, rather than being from the Olympic year itself, then it's quite likely you have a San Cristobal. But in the absence of decals, and a slam dunk date for both your bike and the introduction of the Mockba 80, I don't know if you can be 100% certain. It happens in life.