Judging from the lugs, the dropouts, the fork crown, and the geometry I'll say this is a Modelo 800 or equivalent made with Hi-Ten steel. I highly doubt it is Columus Zeta or Ishiwata tubing.
Clearly a bottom line model almost exactly like the one put on eBay recently.
I doubt this one is prone to cracking where the seatube enters the bottom-bracket lug.
Can't tell whether this bike is just prior to production in Mexico or an actual made in Mexico bike.
When taking pictures of a bike it is very important to cover the following locations:
1. Both sides of the toptube as it approaches the headtube. (Usual model name location...)
2. The front portion of the seatube top to bottom. (Tube indicator and locale location.)
3. Closeup of the fork crown including the start of the fork tubes. (Tube indicator location.)
=8-)