Seems that they repaint that L1011 every two years. When I was based there I've seen it in 2 different colors. This is third version since 2017
I actually wanted to go inside for this colors, but of course the museum was closed for no particular reason.
This is my version from early 2018
Oh, and the museum actually opens at 5pm, and it's closed at every single holiday + on Sundays or Thursdays (forgot already).
Their website suggest that they open 8am daily, but that's not true. On the days they are open it's always 5-ish (five-ish because depends what time soldiers come to the ticket booth from the base). This is the only aviation related attraction in Riyadh, and if you want to visit it, shoot for 5pm on the days they would be open. The only time I had luck with it, was on either Friday 5pm or Saturday 5pm.
It's well worth the visit. Some nice and interesting exhibits inside.