I don't know if you're being serious about this?
Hey
Mouse Vader ! Don't call me Shirley.

And yes, they are very difficult to find. Panasonic has made some: Red, Green, and Yellow. I have one that I bought from Digikey, or was it Mouser, this headache I have won't let me think straight, hold on...
Digikey...
LNG312GKG Panasonic Electronic Components | Optoelectronics | DigiKey
Mouser has this one...
https://www.mouser.com/ProductDetai...=sGAEpiMZZMuCm2JlHBGefn/LkibD1bsSjQOIoJUuY9s=
I didn't get the Lumex one because the datasheet specs showed it to be the wrong shape and too small in size to be corrected.
The Panasonic one is closer to being an isosceles triangle but still needs a bit of sanding to be true. The color is also off, it's more yellow-green than grass green when lit, and looks like Coke-Glass.
The ones in
James Kenobi 1138 's photos look like the ones from KR. They're isosceles, but slightly too big.
Hey
James Kenobi 1138 ! Do you have any photos you could share of yours lit up?
Where was I... brains, brains, BRAINS! Oh yeah, so they're difficult to find, if that's what they actually were. I've scoured through a couple of A/V sites that have hundreds of photos of tapedecks, answering machines, etc. trying to find 'em, but no luck yet.
I'm more willing to bet that the prop was made using a found part, rather than a part made specifically for this piece. It's probably some wildly obscure part like the UP/DOWN indicator on an airliner dumbwaiter.
It could also be that someone made a sketch in the art department that had arrows on the activation box and someone in the prop department simply filed down 5mm LEDs to match the artist's sketch.
How many licks does it take to get to the center of a lightsaber-mystery-part-pop? The world may never know.