Polyester and polypropylene can be cleaned in much the same way since they're both hard to hurt, and both hold on to oils more than nylon.
The oxi-everything cleaners will take color out of nylon carpet though, and if the customer hasn't noticed the chemical-induced fading you've been lucky.
Type 6 nylon will accept stains more readily than other plastics (Ever wonder why you have more trouble getting coffee out of some carpet? It's type 6) Type 6 is also more easily damaged by oxi-morons, and a leaky fitting will bleach all the color from the area that gets wet.
100% acrylic carpet is rare, but can turn brown in the presence of acids. Treat the "browning" with acid and you get more browning.
So yeah, it's good to know the difference.
Its bad enough that idiots are making area rugs out of viscose and lyocell. Now they are making wall to wall carpet with the stuff. If you think polyester and triexta are garbage, wait till you get one of these.
We cleaned an installed carpet from Stark that was 50/50 rayon/wool. The yarns themselves were blended, so no easy way to tell. It turned yellow as it dried and could not be fixed. The customer information from Stark said it was 100% wool. Sad that a once great company has stooped to cheating customers this way.