It costs nothing to add the source and/or quote tags and remove any doubt. Here is a another one, unprompted spammy copy-pasta (and no, the link at the bottom is not a link to a source):
The "time stamps" are from the Youtube video description. He seems to have copied them from there, so in this case it is indeed a source link.
It's not. The first sentence is from yurimir's post so it's copied from there (or they both copied from somewhere else) without a reference.