Sorry I just missed your post, my bad. Sure, I can.
A. Modifications of SVD.
1. A modified LSS XL Gen-2 stock from MDT in place of original. Modified because they made it foldable, the original is fixed.
2. Pistol grip is the same that's offered by MDT.
3. It's hard to say about the top rails and handguard assembly, as there aren't much media related to SSS's SVD available.
B. Now coming to P-72s.
1. The buttstock assembly is the same used on Masada/ACR. In some pics it seems like they tried to replicate that by 3D printing. Design wise, ditto.
2. In some pics the pistol grip is the one from MDT and in others it's the good ol' A2 grip of AR-15.
3. I'm pretty sure that an AK Fire Control Group is used. How? Guessing by the position of hammer and trigger pins. Also if you look closely, the fire selector switch's "wings" are reversed on both sides, a telltale sign of Kalashnikovs.
4. It uses AK mags. In some pics it's Magpul and in some it's PRO MAG (ya pro mag
).
The magazine release is same paddle type, just the paddle levers are turned 90° instead of straight. As an AK mag, there is no Bolt Hold Open.
5. The bolt carrier group seems like a modified AK one. Modifications including a new bolt carrier with charging handle and no attached bolt carrier extension or piston. This also means they changed the recoil spring assembly.
6. Not sure, but it can be a short stroke piston operated. Not a big deal, given there past experience with Dragunov which is also a SS piston rifle. The piston heads of both AK and SVD are of 10-12mm diameter, so again it can used there.
7. The upper-lower-handguard seems bit dubious to me. In some pics it looks like stamped sheet steel, milled aluminium in some and interestingly the texture in some pics resemble 3D printed plastic.
Again these are what I deduced solely from some pics. I can be totally wrong here. I'm not claiming something. Anyone can feel free to correct me.