I don’t know where the info about Grom being based on the KH-23 comes from. From the images I saw and generally reading about it in articles, I have the impression that the development comes from US-based AGM systems. Added an image as an example. It looks far more like a SACLOS copy of a Maveric than anything to do with the KH-23 family.
Note: It had 2 motors, one in the back and the one in the middle that looks like a kh23 motor(Booster + solid-fuel sustainer motor)
edit 2: Found official sources, yes was mistaken, it did use the KH-23 as a base.
The VRVZ-24 is the older prototype name, the VRVZ-240 is the newer pre-production/production name, I think. As I saw with a lot of other weapon types, they just add a 0 at the end or similar.
The name comes from the S24 rocket; it, after all, was the basis for the VRVZ-24/240 from what I understand, hence why I said it is the old prototype name, as it was showcased for the first time in its full form in 2017 partner. And as stated in the image below it was first showcased with the 24, then later on (renamed)showcased as the 240…
The VRVZ-24 is indeed a VRVZ-240 as Pfodyeo said, but it uses what I assume is GNSS/GPS (if it were in game). It looks a bit different but the brochures show the same stats. Also it shows it having 123kg warhead (which I tried reporting, but it did not work for some reason, stating warhead isn’t explosive size Community Bug Reporting System). I really doubt it has a 123kg warhead but just that little of explosives inside ngl. Anyway.
This is also further reinforced with the E-24-1, which is an upgrade to the E-24. Also, the file name of the brochure calls the E-24-1 as the “VRVZ E-24-1”
TLDR: It uses the same body/came from the S-24 rocket, where the VRVZ-240 came from too. The main difference is just the seeker as well as some differences on the body like the fins along the body for example
