D100 Bed Liner

Was looking online for a drop-in bed liner for my '77 D100 short bed, widebox and having no luck. Are they really not available anymore?

I can't answer about the drop-in.
If you can't find one, look in a B cargo van.
Saw a 2003 at the u pull it yard.
It had a huge rubber mat that appeared to be factory, as it was under the cargo barriers in the front. Anyway, this thing is wide enough that I'm sure you could trim it to fit your D-100.
Not as good, but offers a lot of protection, and cargo won't slide.