are the colors different due to its stage of development? When this species molts does it change in color that much? I will check it out more in the image of other spp accounts.

They do change color a bit as they grow, but both of these on BugGuide look nearly full grown to me. There are no two of these that look exactly the same. Actually both photos on BugGuide look a bit odd to me, because I am used to seeing most of them (in the Albuquerque - Belen area) with more developed thin dark cross stripes between the main ones, and more of an overall grayish or bluish color, often with distinct orange markings. They feed on primarily on Portulacaceae such as Portulaca, Talinum, Talinopsis, etc., including the Mossrose in your garden. The Portulaca retusa in your photos is actually a New Mexico native. The photo on the AZ website shows the larva on Talinum (probably T. whitei). They will feed on new cactus growth in captivity too, particularly the young leaves of cholla or pricklypear, but I have not seen them on cacti in the wild yet. If you see a similar one on cacti, it is probably Euscirrhopterus cosyra. The adults of E. gloveri are similar to that species, but average a tad smaller, and the silver-white stripe across the front wing is almost divided in the middle. E. gloveri is very common across much of New Mexico. I'll try to remember to shoot some photos this year. My son calls them Portulaca Underwings, or Portulaca Moths.

Are you saying that both of these caterpillar images are E. gloveri?

That's what I get for writing so much and forgetting the main question. They are the same thing.