Well, I guessed correctly about which Samuel Schwartz was MY paternal great-uncle Samuel Schwartz (see my Searching for Uncle Sam post from February). I just received the death certificate and it's clearly the right Great-Uncle Sam, not some other person unrelated to my family.
Now I know exactly when he died and where he was buried. His second wife didn't give any details such as birth date or home town when providing info for the death cert, unfortunately, but I'm not surprised about that.
What was a surprise is that he's buried in the same cemetery as his first wife, which coincidentally is the same cemetery where my paternal grandparents are buried. Is it a coincidence? Well, I have a plot plan for where my paternal ancestors are buried and Uncle Sam's name doesn't appear on it. I'll check with the cemetery for more about the area in which Uncle Sam is buried. Maybe other relatives are buried nearby?
What I learned: Pay attention to the stories that relatives tell. One cousin said she believed this relative had a heart attack while mowing his lawn on a hot summer day--and it turns out she was right, he died in June. Another cousin was able to narrow down the range of years for when my great-uncle died, and he was right. Otherwise it would have been impossible for me to take an educated guess. I would have spent much more time and money searching for Great-Uncle Sam.