Looking at J. David Conrad's
The Steam Locomotive Directory of North America (now out of print) I find the following G-030 engines listed as displayed in Mexico:
262 BLW 1921 Monterrey, NL
269 BLW 1921 Toluca, Mex.
272 BLW 1921 Jalspa, Ver
279 BLW 1921 Cuaulia, Mor.
Here are some G-023s
67 Schenectady 1899 Mexico, DF
69 Schenectady 1899 Nacozari de Garcia, Son
70 Schenectady 1899 Empalme, Son
And one G-024:
143 Kerr, Stuart & Co. 1904 Oriental, Pue.
Brian Norden