I just bought a songwriter and now but, saddle and bridge pins are all tusq. It is not plastic, but a polymer formed at great pressure and heat. Is is far superior to bone, Ivory, or ebony.
I also have a Taylor and it too has tusq nut and saddle but it does have ebony bridge pins.
Both guitars sound phenomenal. The Taylor just pips the Gibson but I just put some Ernie ball light and silk stings on the Taylor and they are just amazing.