Dart/Duster Washer Res/Rad Overflow

That condition is somewhat typical. I sold a unbroken 73 coolant reservoir to a member here once and my finger went right through the top of it before I could get it in a box. I'm just glad it happened then and not during his install. Good luck to all.
I know you are right, hopefully I’ll get lucky and somebody has some that will work for what I’m needing.