I must finish F2 first and check if this mod adhers to FNV established canon on the diverted origins of Rangers.
as in F1 there's a recruitalble companion in Junktown named Tycho. he lived in the innermost section of the town in a saloon (can't remember a name but it has an urn on the counter), a dialogue options with him revealed that he was a desert ranger who came from what that once was Nevada (he said nothing of Vegas but possibly he might have waked Mojave before)
Well, the mod development started long before Obsidian even worked on New Vegas (it took them 10 years to release the mod for the first time), and as I said before it took place in the region much further east of Nevada (and even Arizona), which is exactly New Mexico with Albuquerque being roughly in the center of its overworld map. So, just like Fallout of Nevada, you can assume the mod will have little to no connection to the New Vegas, and have much more to do with Fallout 1 since it takes place sometime after it. However, the difference between Nevada and 1.5 is that Nevada take place in Vault City, New Reno, and also Las Vegas, but even then the author did his best to separate New Vegas from Nevada by only have some implications here and there in Las Vegas area. Meanwhile, 1.5 have literally zero to do with any of the main entries other than Fallout 1, so if you really want to find anything about the Desert Rangers in 1.5, you're going to be disappointed because the only characters to appear in 1.5 that returned from F1 are those who're related to the Hub and the Children of the Cathedral. There's literally zero stuff, implications, or even mentions about the Desert Rangers in 1.5. I should know, I've replayed it so many times and can remember most of the lore and dialogues.
But yes, it's a fact that Tycho, a recruitable companion whom you encounter for the first time in Junktown tavern building, does have dialogues related to the Desert Rangers of Nevada, and New Vegas canonize their existence by having them absorbed by the NCR Rangers. You can even find their outfit in Honest Hearts, iirc. However, based on the information I can gather on the wikia, it seems that the Desert Rangers, while mainly operate in Nevada, can also be found in Arizona. 1.5 took place in New Mexico, an region exactly east of Arizona, and it's not mentioned anywhere where the information about the Desert Rangers is available, so yeah, I can confirm you'll find zero stuff about the Desert Rangers in 1.5