Strange interchangeability of parts

on our 2 flight to US and back
we had 2 different painted 744
on the Gatwick flight out we had an old non metallic red, but had one engine cowl in red metallic
and on the return to Heathrow we had a full metallic paint 744 but 1 engine cowl was in the old red ?|

Think its G-VGAL with the metallic red engine cowl. Been like this for a while as i took this pic back in April:



I guess they just have a stock of parts and they're painted in whatever colour was current at the time of when they took stock.

Theres also an A346 or 2 flying round with white cowlings. And I've seen Barbarella with a mustard yellow patch around the wing.