Those things last a long time, GB. I wouldn't bother to freeze it.
They do freeze well, though. If you found one on sale and didn't want to cook it until after the "use by" date, then freezing would be the answer.
I love corned beef and cabbage, which is a little strange, because my mother never fixed anything like that. I never tasted cooked cabbage until I was 19 years old. My husband will eat the corned beef, but not the cabbage, so I cook the corned beef in the crockpot, remove and let stand, then put the cabbage in the juice to cook it.
Corned beef on rye with mustard, sauerkraut and swiss cheese sure makes a great sandwich.
What are you gonna do with yours, GB?