I took mine out to take pics, if I'd lost it in my mess there'd be spit all over my monitor. It appears to be a 2 piece design, the smaller diameter pin looks like it was inserted in a drilled hole and loc-tited in.
If you find a source, get 3 and send me 1 for a spare.
That does not look like something that can be replaced with a number drill. Question, is the smaller pin spring loaded or a separate part from the main body? If the small pin is removable OP what are you missing, the small pin or the whole thing?