I admit that either possibility is, at minimum, plausible.
They (The ubiquitous “They”) say that Time is a fluid thing and that the very concept of Time Travel is no longer the property of Science Fiction writers. OK, I can accept that, but I just don’t expect it to happen while I’m quietly trying to have a cup of coffee.
Twice in the last month while I was concentrating on getting my plastic straw through the lid on my iced coffee my world was intruded upon by the 1950s and then the 1960s. I’ve been through those decades before so I recognized them immediately.