Stock is for a 1 piece bottom metal. If you're comfortable with a drill and a dremel, you can make the needed adjustment in about 5-10 minutes. I've done is several times.
If you're putting 2-piece BM into a 1-piece stock, you will need an adaptor - should not have to enlarge anything - putting a 1-piece BM into a 2-piece BM stock is where you have to relieve material . . . and shorten the pillars
I know - I just ordered two to go into original two-piece bottom metal stocks and would have had to remove a lot of material at the rear of the magazine but also would have to inlet the entire assembly outline area about 120 thousandths deeper - that's bad enough but I was not about to grind the pillars with a dremel and re-bed the bottom metal.
The other option would be to mill the bottom-metal thinner - having said that, let me add that the PT&G bottom metal is the best deal on the market - just hope that they will make a version for those New Haven M70 Classics that have the two-piece bottom metal so no stock mod's are necessary.