Would this be Soft Plastic?

[markosjal]

I found this for sale , sorry only one Pic.  It looks to me like soft plastic based on handset markings and fingerwheel type.

One might never get rid of the yellowing though.

[Kenton K]

It might be a mix, based on the different degrees of yellowing on the dial face and body. Mixes were common as they used up the remaining soft plastic stock. The handset caps and dial face look soft to me

[Stubbypylon]

Soft plastic does have a different sound when you tap on it with your finger.  Also another indication might be dates stamped in vermilion ink inside the handset caps, housing, and back of the dial.

[MMikeJBenN27]

The most foolproof way to tell is the smell.  Soft plastic smells like stale cheese.

Mike