A pastel is a Pastel, yes there are different lines but unless you buy directly from NERD or someone that is very meticulous about keeping track of their lineage (and has only Lemon to Lemon) identifying a certain line is impossible, they have been around a long time and lines have been crossed into each other.
When breeding Pastels to me it's a matter of selective breeding using the best example possible the line does not matter much.
I have some Lemon in my clown project, I also work with Graziani in another project and with some animals I have no idea what line of Pastel has been used to produce them, all that matter is those animals are great example.