I would guess it is malaysian, by the lot # markings and the presence of the wire seal. Made in 1981 which would jive with the year range that was surplused by Malaysia.
Malaysian ammo has sort of a weird rep. Some people with tell you it's hot, has a large muzzle flash, corroded or tarnished cases, and/or poor quality control. Other people will tell you it's hot, highly reliable, accurate, and the brass is considered great to reload. Generally though, it has a pretty good rep. One thing is for certain, the ammo is hot, 3250 fps out of a 16" barrel, hot. In other words, you can get the performance of a 20" barrel with a 16" barrel by shooting this ammo.
As for my experience with it, it was hot, very reliable, very low muzzle flash, but I did find small spots of corrosion on some cases. The corrosion wasn't as bad as some guatemalan that I bought, and it wasn't bad enough to cause any concern over safety issues. I would definitely buy it for that price, being that it is still in a sealed can should mean it is in pretty good condition.