That's right. I've been able to find a few references to AM's HS-748s but no photos. At one time the fleet numbered 5. From what I can gather, the aircraft may have been operated by Servicios Aerieos Especiales on behalf of AM. If anyone out there could offer a definitive answer, WHBM would be the man.
Yes, a predecessor Mexican airline, Aeromaya, had a couple, after merging into SAESA the year before our question they bought three more new ones. Two were lost quite soon, the others, like most 748s in North America, were then sold on in Canada, where they lasted for many years. SAESA seem to have been somewhat associated with Aeromexico. These were the only 748s to operate in the country.
http://www.airlinefan.com/airline-ph...HS-748/XA-SAB/
The 748 scored over the Fokker/Fairchild F27 in Canada by its robust undercarriage, which suited gravel runways much better than the long-legged F27 under its high wing.
OAG code AO for Avro. The Hawker Siddeley company had owned several manufacturers for a long time, Avro since the mid-1930s, likewise the Hawker Hurricane of WW2 prominence, De Havilland, and others, all with their own design teams and separate factories, although behind the scenes they subcontracted a lot of parts between one another. A change in corporate policy in 1963 led to the whole organisation being rebranded as Hawker Siddeley, just a year or so after the first Avro 748s came along, but the OAG code stuck (in our equivalent ABC timetable over here it was HS7). The name Avro was resuscitated in more recent times on the "BAe146-Neo", one of which I can hear taking off from London City just as I type this !