Yeah, they sure do look like timestamps. I have a program that I used daily to record Sirius Patriot programs with a scheduler, and it writes files that look like that.
However, if this is an actual filename from a laptop purchase as new a week ago, I doesn't seem logical that to have a timestamp from 2017. Perhaps it was imported from a backup when the OP retrieved files from his recently-deceased machine.
I'd wonder if the OP has been able to discern the 'freshness' of these conversations in which he recognizes his voice. It ought to be easy enough to say 'I remember talking about that the other day'. For some mundane conversation from September of 2017, not so much...
First thing I'd do -- after running Malwarebytes and another security tool or two -- would be to locate where these files are stored on the machine.
He makes it clear in the comments there, that these files came from his old computer. They weren’t visible on the old computer, but when he transferred all the files from his old computer to an external drive, they became unhidden.