yes, MBK dial will fit the PT
im not sure if you mean the MBK coronet has a small opening, or the PT, but the most recent MBK dials are just fine.
many people seem to be searching for them all of a sudden right now. apparently theyre out of stock from sellers till february.
im not sure about sanding the bezel insert, ive tried gen insert on an MBK and it fits 100% correctly with no sanding.
315-5513 i believe is the correct part no. you can also search 5513,1680,1665 insert
some come with pearls some dont, w/pearl the price is higher, ofrei fits certain styles despite sharing the same part no. universally. my gen insert from the 80s the ofrei was slightly too wide, had to enlarge the insert hole just a wee bit.