Last night I got the magazine tube polished out to 400 grit. This may be as far as I'll take it. It is much smother than the factory machined finish and I can see my reflection in it.
The goal for today is to get the barrel to the same finish. This takes more time as I have to avoid the sweated on front sight ramp and I have to avoid rubbing out the lettering on the barrel.
I was wrong in stating that this was a pre-64 gun. I found better information that indicates this gun was made in 1974 and extrapolating the numbers gives me a guesstimation manufacture month of November or December. This gun has a prefix number of 401 and 1975 guns started with 411.