Which parts exactly are "take-off" parts on the M24R?
On mine it was clearly the stock and bottom metal. Per Remington's contract with the US Army, all serviceable parts that were removed for the M2010 program could be re-used on the M24R rebuilds. I think Remington apparently refinished some parts, ie, scope mounts, iron sight blocks, etc, so its hard to say exactly what small parts are take-off versus replaced parts. I think the old Redfield iron sight mounting blocks are refinished original parts, as the originals haven't been made since the late 80s. (Mine has the later OK Weber iron sight mounts which are a little different than the late 1980's Redfield parts).
To the best of my knowledge, there were 3 parts that were
always new on the M24Rs:
1.
M24R receiver's are new as the US Army re-used the serviceable ones for the M2010s, and US Army will not allow its serial numbered receivers to be re-sold to the public. (Note: Any M24/M2010 receiver that develops or exhibits a potential issue is destroyed by Remington as part of their support contract with the DoD).
2.
M24 fire control unit (trigger and safety) are new, as it would be too much liability for Remington to re-sell a used trigger unit that might be been modified, worn-out, or otherwise 'messed with' in its military service, resulting in a unsafe firing mechanism. The new M24R triggers went through the same rigerous testing protocol that the military requires.
3.
M24 barrels are new for obvious reasons - who wants to buy an M24R with a potentially worn-out barrel? Again, these are mil-spec M24 barrels that go through an extra honing process by Remington Defense, stamped '7.62 NATO' etc.
As for the other small parts, if they were serviceable they were apparently refinished and re-used. If not, they were replaced. Some kits had painted scope rings, scope rails, and some Harris bipods that matched the camo job on the stock, but I was not lucky enough to get the whole kit with such parts. (Pic #4 is not my M24R, but it came with the take-off/matching Leupold M3A optic and the long discontinued one-piece scope rail. I am 99% sure the scope, sunshade, rings, and scope rail are associated with that painted M24 stock while in military service....not all M24Rs had that level of matching take-off parts, but many did).
My take-off optic is a 1989 dated M3A Ultra that had its camo paint removed at some point in the past, with only some remaining on the rear lens cover, etc. I had it sent back to Leupold for a no-cost Warranty/Inspection process as it had fine grit or debris in the rear ocular. They replaced that glass and reticle and returned the scope to me with all the patina in tact, but with new glass. Rings are also take-off parts.
As noted in the last picture, my projects often start with a take-off stock: M40A1 on top, and my Navy Mk 13 Mod 3 project is in process (bottom stock).