We are taking a vacation.
I now see that I'm well overdue.
Why?
Because all along I was thinking this thread was about exterior lighting.

Now to get back on topic.
I'd have to guess the interior lights are indeed LED's.
At least on the SLT-2.
The illumination is typical of LED lighting.
It may be the clusters of very small LED's that are encased in a bayonnet style housing (I can't remember the exact term for the housing at the moment) or it may be the high intensity LED's, either singles or two's or three's per area.
Whatever the case may be, I'd guess 99.9% that the interior is indeed illuminated with LED lighting.