Factory red K/20 hub knobs???

[Robert1970C20rstbukt]

I was looking at the 4x4 parts in the 1970 Chevrolet 10-60 series parts book and came across this:

Gr. 6.308

Ser. 20 (4/WD) w/ locking hubs 3958034 Gasket, retainer(Dana 35379) Note 1

Note 1- Used with a red plastic actuator knob

What?!?! According to that, there were some red knobs used from the factory on K/20's. I guess the knobs on my K/20 Suburban are original. They have the SPICER center on the knob and they're red. There isn't a K/20 knob listed in the book, it only has one for K/10's but it doesn't mention the color:

Gr. 6.308

Ser. 10, Blazer (4/WD) w/ locking hubs 3937068 Knob, actuating (Dana 34916-1)

Back then that only cost $2!

I know some of y'all have NOS blue knobs, what's the part number on 'em? I'll have to pull one off the Suburban and see what the number for those is. Does anybody else have a truck that had the red ones on 'em?