Can somebody tell me if 338/06 a-square is dimensionally the same as 338-06 sized up from 30/06 brass. Looking to buy a set of dies and am seeing both for sale. Thank you.

They are, or should be the same; AA just put his name on the 338-06; however, no one really knows what your chamber is like except the guy who cut it; Ask him.
How is your rifle marked?
338-06 is a great round. I do a lot of them.

DPCD is correct.
My pre-64 Model 70 chambers the A-square cases and my own. They should be identical.
It is still one of the best hunting cartridges-period- across the board.

Good to know, thank you. Both marked 338/06, I have dedicated dies for all my rifles, just needing another set of dies.