For me, It seem to be a simple "T-shirt" with this two holsters. So no, i never seen that (T-Shirt, yes off course)
For Meredith's, i think i saw a green (light green) one, but nothing exactly the same
Much like Meredith's dress and shoes, I don't believe those shirts are listed in the console commands (I do have the AIO Console Commands excel spreadsheet and can't find them/ it). This means that they are not available for players, either through world pick up or console commands.
Meredith's breastplate (MILITECH ULTRALIGHT ARAMID BREASTPLATE) isn't available without console commands so far as I'm aware either, heh ':/