What Muchxs said is correct. Low AF amps like this design are not very concerned about oscillation, RF and EMI incursions, etc.
This layout is a typical Nathan Daniel cost control design which took advantage of that fact. He looked at the application's REAL requirements and found ways to cut the production cost by the elimination of parts (which is more than just parts cost reduction, it is LABOR reduction. That is where the real savings were found)
Putting the vol control before V1 provides the grid leak and volume control in one component. Savings 1 resistor and the labor to install it. Switching jacks cost money, about twice what a non switcher costs, plus the labor to wire them and the 1meg resistor x 2. Again, savings on four components. Mr. Daniel was affectionately known for what we engineer types call "Value Engineering". He was a genius at that fine art, and at coaxing maximum value out of a design.
That's what this is.