the pair i am getting is supposedly 20 or so years old. i dont know what type of lens coatings they will have. im sure they will have multi coatings, but how would you tell if they are phase coated? oiginal owner did not have the box.
The T* multi-layer AR coating came in in the late 1970s (IIRC) so they probably will have a ML coating. Easy to check by the color of the reflected light: purple or green for ML; distincly blue single layer MgF.
Phase coating is right on the bubble for a 20 year old Zeiss. It came in on the Dialyt's in 1988. So the odds are it doesn't have PC if it is 20 years old.
With resolution charts that you can rotate (and align to the roof edge of the roof prisms) you could probably make the measurement to check. Without PC the resolution perpendicular to the roof edge (i.e. with the lines on the chart running parallel to the roof edge) will be about 2 to 3 times worse than at right angles to that. So measure the resolution of the bin (with a booster telescope to take your eyes out of the calculation) with and across the roof edge direction.
You find the direction of the roof by looking though the objective (perhaps with a flashlight). It will be different for each barrel and it won't be vertical or horizontal (to avoid you noticing the effect in a man-made environment).
Someone used to looking at roofs of that era should also get a feel for the change in the view: a little less sharp and a little less contrasty.
Another approach: take the serial number and ask Zeiss ...
