The M70 will be a much better hunting rifle, the M1 will be better for target practice at the range.
My advice if you don't know anything about an M1 is get detailed pictures take them or the rifle if the owner will agree to someone who can value both. A good place to get info on M1's would be to hang out on the CMP forums. There used to be a few companies that built M1's out of spare surplus parts, and those rifles don't have the value of correct manufacture M1 rifles.
Don't be in a hurry to make the trade, take time and do the research and if you want to make the trade go for it.