The New England Genealogical Historical Society on Newbury Street also has a copy of the index books from 1900 to 1980. If you happen to be a member, you might try calling there (4th floor) and perhaps someone at the research desk would do a quick look up for you so you have the year of death. I have found the staff there to be very helpful - I know they do charge for hourly research, but this should take them just a few minutes so they may do it for free if you catch them at a slower time.