It seems that if you upgrade the trigger guard then you'll be fine. Here's the notice from Boyd's when ordering the stock.
ATTENTION CUSTOMERS: This stock is designed to fit the Marlin Model 60 tube feed with the newer trigger guard style. Early model trigger guards are longer and are shaped differently. DIP Products sells newer version trigger guards for the Model 60, if needed. May also require aftermarket screws not supplied by DIP or Boyds.