M_Boats: M15 Ballast Question

I know that the M15 and M17 were originally produced using iron punchings as ballast. Documentation from Jerry Montgomery on MSOG indicates that the ballast was changed to lead in 1987 for the M17. Was the ballast changed to lead at the same time for the M15? If not, was it ever changed to lead? Thanks for any information Fair Winds Jobst Looking for an M15 of my own __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com