any way to tell what spring rates are
 

obviously, you can measure them with a known weight, but anything besides that? stampings? labeling?

There are paint dots on the springs. Not sure of how the codeing works on that, but may be in the workshop manual.

where are these dots?

The dots are on the coils of the springs. They are just dabs of paint really not dots, should be three close together that can be deciphered in the manual.

If your springs are stock you can look them up here by model/year (page 5):

http://clarks-garage.com/pdf-manual/susp-15.pdf

Spring rates are easy to determine. Just measure diameter of the coil and wire. Count the number of coils and calculate. You don't even have to take them off the car to measure and calculate.

Equation: k = Gd4/8nD3
Having a little trouble getting the upper case font. That equation is d to the 4th power and D to the 3rd.

Where:
k = Spirng Constant, pounds of load per inch of deflection
G = modulus of rigidity of spring material, = 12,000,000 lb/in2.
d = wire diameter, inches
n = number of active coils, which is the number of coils subjected to flexure
D = mean coil diameter, inches = Outer Diameter - Wire Diameter


http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/637982-weltmeister-green-stripe.html


Suspension Coil Spring Rate Design Equations Formulas Calculator

thanks, i bought some koni cored struts and didnt know if the PO had aftermarket springs on it them, it appears he did not. which is exactly what i needed to know, thanks!

Quite interesting. So, the number that we get as a result of applying this formula, is it consistent with what we all call "250# springs?"