As I tried to answer in your previous post, to the best of my knowledge your GLT came with the same springs as the base model:
o Ride height listed for 1985 Volvo 240 DL Automatic is 1430 mm (closest year I could find).
o Ride height listed for 1980 Volvo 244 GLT Manual is 1435 mm, so actually 3/16" higher than the DL. If yours is 242 GLT then possibly a hair different.

For the 1985, some of the difference might be explained by weight differences between the AW60 trans and manual you likely have, also the B230F LH-Jet engine compared to the B23E K-Jet I presume you have. It may also be a case where someone rounded a measurement up to inches than back down to metric.

The real question is whether a PO has already modded the suspension.

If yours measures 1"-2"(25-50 mm) lower than those ride heights when completely unloaded then yours may well not have stock suspension. For less than a 1" ride height difference, you can't be certain you're precisely matching the loading used for their measurement (totally unloaded? tank full? empty? half?), plus 43 years of spring metal fatigue.

You can also check out stock photos for a visual comparison of ride height between the GLT vs. DLs of those years (choose same bumper, grill and hood profile). GLT's may appear to ride lower with their low profile tires on 15" alloys, also if 2-door then the window profile makes them look a little sleaker and lower.

Like I said, inspect the coils you have to see if the fronts are progressively wound (ie. are already ipd sport coils). Count the coils and note the end offsets. You can also check the coil diameter. The stock pre-1986 front coils are listed as p/n 1229137, 7-1/2 turns, o.d. 13.9 mm (13.85 mm to be more precise). Fitment is listed for all models. Your rear springs are either p/n 1212426 12mm or p/n 1229052 13mm (12.9 mm), the turns aren't mentioned. Fitment for the heavier rear springs is noted as for the later wagons and GL/GLE/GT/GLT, but an unspecified year change is mentioned, so if yours measures 12mm then that's why.

If you spend some time with Google there's lots to be found out there on 240 overall specifications and suspension discussions, including this page on Dave Barton's site;
https://www.240turbo.com/suspension.html

Do you want to lower it for looks or handling? If the answer is handling, the general consensus was to start with stiffer sways (front and rear), poly bushings and plus-sized tires as your first upgrade, then the springs and struts. If you get carried away, you may end up with slightly more responsive handling, but at the cost of a harder ride, harsher than you may like. Way back, hardly any road speed bumps, but these days they're everywhere and many roads are in worse shape than ever. There are also considerations for creating oversteer.

Turbobricks is a better forum than the brickboard for asking these types of questions and checking out previous discussions.