Just came across this thread - and having looked at one of the Hunter pictures in my album it is XL573. It has CFI marked on the back, and the album it is in makes me think it was when my step-dad was CFI of 237 - 85-88, so the picture will date around then.
Possible thread drift - but here are three together-taken I believe towards the end of his stint as OC 237 before it was closed. Not sure of one is XL573 as all the markings are too small. But it's a nice picture.
