I've looked at the marker a few times and am about sure the date is 19 May 1890. As you know the marker was broken across between the dates of birth and death and has been repaired with some compound.The repair material comes across the last digit of the year of death.However, looking closely it does appear that last digit is an "0", so it appears the year was 1890.Also obsured by the repair is the word "died". From the marker:
ARENDA SIMS BORN OCT. 19, 1818
MAY 19, 1890
I've a photo of her grave marker as well as a photo of the grave marker for Lewis Saxton Sims.His has his name on the marker as LOUIS S. SIMS.Will scan and send a copy to you.