Tiny meteorites are everywhere. Here’s how to find them.

I don't think the video mentioned anything about an electron microscope. It's not emphasized, and not present at all in the audio, but there is "mention" within the video. At 8:40 in the video ( [VIDEO] ), when showing the response from Larsen, the sentence after the highlighting reads "a scanning electron microscope (SEM) examination ... would be necessary". So you are right that it wasn't done, but it apparently would have been the next step for a confirmation.

I feel like everyone is scouring their roof for micrometeorites these days. Here's a few videos on the subject: [LINK] [VIDEO]

Here [1] is a great video about Larsen and his work on collecting microscopic meteroites. Larsen's book, "In Search of Stardust: Amazing Micrometeorites and Their Terrestrial Imposters" [2] is also great, a gorgeous coffee table book with lots of high-quality photos of meteorites of the kind that you see on the web site. [1] [VIDEO] [2] [LINK]

Here's a good video running through one way to do this at home - [VIDEO] (I really like the ending, it's real science which is rare these days) There are a heap of better links to micrometeorites stories than this stackexchange. Discussed many times on HN.