while spring diameter may not be exact science , it can be used as a guide to help us figure out aprox spring rate.
here are some measurements I took from the stash of springs

12.88mm = 200#
11.88 = 180#
11.26mm = 165 progressive
10.8mm = 140#?

9.7mm = stock X#

Welt
43/92 SP100 10.7 mm (100#)
67253 SP180 11.7mm (180#)

Eibach
336767 080.250.0225 9.86mm (225#)
1000.250.0175 9.90mm (175#)

So it seems that you can tell with the weltmeisters, but not the Eibachs.

those eibachs would be teh 2.5" and 2.25" smaller type used on adjustable spring perches like ground control. your part number indicates 2.5"

Both Eibachs are 2.5" One I got from the PO is a 175# and the ones I just got from ground control are 225#