These are both later 20th century bottles - no older than about 1960 - and they are machine made. The fully automated machine process came into use in the 1910s-20s era.
The stippling (dots) around the edge of the base are telling of their age.
I do believe the feature shown in the first photo is there to help control the grip of the bottle while handled in automated processes. Tried unsuccessfully to find the reference to this that I have previously seen online.
You will find Bill Lindsey's site (http://www.sha.org/bottle/index.htm) to be of help for further details on mass produced 20th century bottles.
Chris
