Nowhere near an expert on land forces so lots of guesswork going on here. Does it look reasonable?
Composition of a regular Mexican infantry division:
3 - 4,000 man brigades
3 - 1,000 man battalions (one motorized), equipped with 7/57 Mausers 36 rifles, 7/57 Mendoza 34 LMGs, 81mm mortars, and 30cal HMGs
1 - 1,000 man support battalion, includes three 15 gun 75mm batteries
3 - 15 car reconnaissance squadrons
1 - 3,000 man special weapons brigade
1 - 1,000 man cavalry battalion
1 - 15 tank squadron, AT-31M
3 - 15 gun AT batteries, 47mm
3 - 15 gun AA batteries, 25.4mm
1 - 15 plane squadron, light recon
? - misc other units