Hi, Kev:
Yup, I agree on the different needlebeams.
I don't see any evidence of baggage/combine style X bracing, though in the pictures I have. Just a single angled support to the queenpost.
I suggest unless you find indisputable evidence of X bracing, don't build them like that because it would be very non-standard, since the X bracing was added to provide extra support for freight and baggage. Just my 2 cents worth.
Do either of these cars survive? Are they at Knotts?
Mike