Provided the grease is applied in the right places that brand should be fine. Back in the 80's Lubriuplate was a choice lube. There are a number of synthetics that are popular now.
Dismounting the M1A is not a game breaker. A rifle tuned for best accuracy has an epoxy bed to stabilize the system. Dismounting increases the possibility of damaging or shortening the life of the bedding. In a non bedded rifle it's not an issue but unless there is a serious maintenance problem there is no need to do it.
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