Mk1 rear springs - Jamex 1375 - whats it mean

I've just pulled some rear struts of a Mk1 hatch in a scrap yard. They're red and marked 'Jamex 1375'. Does anyone know what this manufacturers spec is.

Does it tell me ride height/poundage. I've got a Cabrio (1985 injected) with std springs on front and Scirocco springs on the rear. The rear started sitting low when I fitted these old Scirocco springs- I just did it to pass MOT. Will these Jamex ones suit/level my Cab?