I imagine a 25 year old front 240 coil spring in the strut assembly may decompress a bit after hanging for a month.

You should be able to see whether the gland nut that secures the strut cartridge piston inside the strut housing is coming unsecured. Though doubtful if a quality gland nut like which came with the Made in Germany Boge OEM struts factory installed.

How are the strut mounts? These can also slowly sag. Yet when you let the unibody back down on the tires, check the strut mounts for severe doming, separation of the bushing material from the center bearing assembly, or, worse and dangerous, concentric cranks in the bushing material around the center bearings assembly. As you describe the front strut assemblies slowly lowered over a one month period, probably not a problem.

If buying new strut mounts, safest bet are the Made by Germany Boge OEM Volvo strut mounts Volvo PN 1272455. (Avoid aftermarket, until Volvo Cars AB build these parts in China at the Geely factory also.)

Impossible to buy Made in Germany much of anything anymore thanks to the auto part industry. They still build them in Europa, though. Maybe we can get grey market car parts for your Volvo, like you used to import a Volvo 240 as a grey market import on the Volvo Tourist and Diplomat Sales. Oh well.

cheers,

Dud.
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The Volvo 164: The Mightiest of All Volvo Automobiles in Perpetuity