Not necessarily--I produced some really interesting-looking dark lessers last year that looked like high-quality mojaves as hatchlings. While most people clearly prefer very light colored lessers, dark does not automatically signify low quality--it may be the start of a new bloodline that looks spectacular, but very different from the norm. No one would call a Graziani pastel low quality because it's not as yellow as a lemon pastel--nor call a lemon pastel low quality because it has no blushing.
In general, your lower quality lessers will be darker, and could be mistaken for a mojave by someone not very familiar with both morphs--but lower quality lessers also won't be very memorable.
IMO, the practice of selecting mojaves for high yellow is adding to the confusion. To ME, the best mojaves aren't yellow as adults--instead, they have a pale cream color where the yellow would be, and lots of contrast and blushing.
He had two possible fathers. One was a lesser and the other a mojave. I'll admit that looking at him you would say mojave no doubt but the tricky part is that his mom is my Garcia line chocolate. Got me wondering if a chocolate lesser might look like a mojave. I bred him to a pet store mystic looking girl so I really needed him to be a mojave and that was what his babies came out proving. Didn't prove the female but will try again next year just in case I missed the combo.
I'm for sure holding back a daughter with maybe even a little more fading and probably also a 2nd one about like dad. Wondering though if for the combos like mystic potion and mojave GHI if the faded mojave might backfire on me. Maybe you want darker mojaves for those? It will be a long time before I get to find out and I also want to belatedly get to hypo mojave. Maybe this line will work well for the hypo mojave combo.