As pointed out, the ATF rule is just a rule, but odds are astronomical that it will change. The M14s won't be alowed in civillian hands because they are machineguns. It's easier for the govt to just fall back on that than do something to change it.
Military M14s aren't registered in the legal sense. They are definately accounted for always though. Unlike many federal LE agencies that loose guns all the time, the Army rarely looses things like these. They are tracked by serial number on the unit's property book, and then by the unit to the individual when they are issued out from the arms room. Loss of a weapon would result in the ending of several careers so they are far more tracked than most things on Earth.
We did give a bunch away. We probably won't do that much anymore. The reality of aid is it's not just to help a needy ally. It's also a way to make money for the Military-Industrial Complex, and line the pockets of Congresscritters. OK, that may be a bit harsh, but not far from the truth. The US will give brand new M16A2s to a country now, because not only does that country get it's guns, but the manufacturer gets money, and the Congressman keeps jobs in his area. It doesn't matter that it costs the taxpayer three times more to do it that way than send over old M16A1s. It has more to do with taking your money and spreading it around to everyone.
Another great example of this is Afghanistan. We collect up and destroy AKs, then contract and pay Romainia to send new AKs there to arm the Afgahans. Our ally Romainia gets a huge economic boost for helping us out (they do have troops there) and the US taxpayer foots the bill again. Why not just keep all the AKs and reissue them? wouldn't that be cheaper? It's got nothing to do with being cheaper or smarter. It's got to do wtih how much money can someone make off it.
Unfortunately, the US govt has ran such a large budget that unless there's several billions invovled, they don't even bat an eye. To Congress it's chump change and not worth dealing with. Easier to just fall back on the lame "rule" excuse.
Anyway, I see the best result would be the availability of parts through the CMP. The CMP had looked at building M14's in the past with civillian recievers and US parts, but there isn't enough money in it to make it worth it. Production costs, etc. would be too high.
As for if the govt needs a 7.62 rifle in the future, they have a stock of M14's on hand. If there was a need for a 7.62 rifle, they would just spend the millions it would take to make a whole new gun. Afterall, it's not about saving money, it's about spending it.
Ross