Not directly, however, it is possible to convert 25 library parts into 24 library parts - and those parts can be consolidated into a 24 .lfc file - so yes, you could do it in a round about way in you needed to.
If you Backsave a 25 file as a 24 file, the 25 objects can be converted to 24 objects.
However, I am not certain that the parts are actually converted as the Save Option indicates, it might be more like they are replaced with matching 24 library parts. To test this out you could place a 25 library part that is not in the 24 library- back save to 24 using the "Convert library objects backward" option and see what it looks like when you open that file with 24.
Before you waste too much time on this, you may want to determine if there are actually any 25 library parts that are new or different from the 24 library parts anyway.
If you are okay with losing GDL capabilities, you could first configure the object in AC25 as you need, then export single object (select object, choose show selection in 3d) as 3ds or 3dm (not sure if AC25 can do that natively, you might need to install addons) then reimport them back in AC24. Again, you might need to install addons to be able to import 3ds.
AC26 ARM // MBP M2 Max // Twinmotion | Corona | Rhino
Longer answer: yes, but that requires a lot of manual work and familiarity with GDL and its inner guts. (Also its plainly impossible, with any object uses newer GDL commands. Those can be sometimes substituted, but again, that's a lot of manual work.)
Lucas Becker | Mostly AC 26 on Mac | Author of SelfGDL | Developer of the GDL plugin for Sublime Text | «Furthermore, I consider that Carth... yearly releases must be destroyed»