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That is definitely the safe way to go, but the gas plug runs all of $35, and simply screws in, no permanent modifications required. It is a nice option to have. I bought one before I received my M1, have yet to install it, but may use it yet. There are, if I recall correctly, two kinds, McCann(?) and Schuster. One dials in, the other has multiple discs with variously sized apertures. Now that I think, garandgear.com sells a no-adjustment-needed hollowed out version. These all vent, or give extra room for gas near the port near the end of the barrel. The burn rate of the powder vs the weight of the projectile (IMR 4895 and a 150 or 168 grain bullet, iirc) combines to form a pressure curve for which the gas system was designed. These plugs allow for a greater variance in said pressure. I have heard, and will stick to it, whether or not it is true, that 170 grain is still the heaviest bullet one should use. It might be 180 grn. But I am not sure enough in my memory to say for a fact. I am sure wiser heads will comment further.
To recap, the adjustable/replacement plugs are a non-permanent handy thing to have around.

Just to add more food for thought on a ton of other information, you might want to read up on the Korean surplus ammo. I am by no means an expert, but the ammo bearing the "KA" headstamp is all corrosively primed, as is my understanding. If'n it is headstamped PS, it should not be corrosive, but there are certain lots that some folks have reported some problems. I just glanced at that, as the only Korean M2 that I bought was found to have the dreaded "KA". This was not something I wanted to deal with, so's I gave the bandoliers worth to a buddy that didn't care one way or the other. He was kind enough to give me a cartridge belt and some other miscellany when I got my rifle, so I thought it was the fair thing to do. I ramble.

Just to wrap up, remember
KA=Korrosive Ammo
PS=Probably Safe (If you google "PS Korean M2 problems, you will undoubtedly find the exhaustive list of lot numbers. I think it was over to the CMP forums that I saw it.)

+1 on the current (hopefully) Greek surplus from the CMP. $98 plus shipping ('round $11, if I am remembering correctly), for 200 rounds, give or take, shipped in an ammo can.