I came across this item on eBay a short while ago. It's obviously the Sc. 163 from the 1918 issue but interestingly is part of something shown as No. 45 of the Ranworth series.
I've not been able to track this series down specifically although I've found a few others in the series from other countries:
Giraffe, Mozambique 1937
Mount Titano, San Marino, 1935
I wonder why this Liberia got included?