I just saw your post. I'm not sure when Welsh & Naulty closed or was sold - Charles W. Naulty, who was my G-Great Grandfather's brother, died in 1929 and his son didn't go into the business. However, a lot of their records seem to have ended up with the George C. Toppitzer Funeral Home. They have a Mourning Museum at Arlington Cemetery in Upper Darby. Some of their records are available from Ancestry as part of the "Pennsylvania Church and Town Records, 1708-1985" Collection, and it includes a lot of burial receipt books from Welsh & Naulty.