The only parts left on the Ciener website are mags. Everything else is o/s. On the negative side, the mag design and the conversion design are both obsolete. 25 round mags for the AR-15/M16 (no LRBHO trip) can be had for $10 or less (Arms Unlimited). Packages with complete Colt branded conversion kits and three, 25 round mags (no LRBHO trip) can be had for ~$180 - they were as low as $140 last November. There might be some collector value in old Atchisson/Ciener products, but as there were a significant number of the kits and mags sold by Atchisson and Ciener, there is no real scarcity.
On the positive side the conversion and mags are made from carbon steel, not stainless steel and polymer as is now common, so if someone wanted to drill, grind, or weld them, the tasks would likely be simplified. In particular, drilling the bolt to put in tungsten weights or welding steel weights to the back of the bolt would probably be easier. Conversely, milling the bolt to make it lighter is also probably easier than for current stainless steel parts.
Possibly, the mags and mag springs could be cut down and reconfigured to a 'flush fit' format (7 or maybe 8 round capacity). There are some owners of "Blaster" .22 AR-15 pistols who desire such a magazine (that does not extend below/outside of the receiver). Modifying current polymer mags to a flush fit format would probably be more challenging for most individuals, and I doubt that the market for flush fit mags is large enough for most commercial mag manufacturers to pursue.
Best of luck.
MHO, YMMV, etc.