The debate on the L144 is not one that you step into lightly. It is true that there is a L144 and a variant of the common bristlenose commonly refered to as the L144. As to how different these two actually are not really known as the real L144s are so so so rare that its hard to compare. I know here in aus there is a line or two of L144 and i believe they were crossed with common bristlenose to give the L144 colour morph.
If they are the same species, or even genus i am not 100% sure. I do know that it complicates the genetics a lot as it means that there is a yellow morph of the common, not just an albino one! makes it damn tricky!
Amber might know a bit more, not something that i have looking into all that much, kind of avoiding that bit of the genetics til i have to look at it