Northroader
The lining is as the loco immediately above. Like quite a few exhibits in Cultra - and in preservation in Ireland in general, liveries are wrong - often nonsensically so, and if I dare say so, inexcusably so. People who are interested in the authentic appearance of something, like your good self, will naturally look to museums and the like for what ought to be accurate information.
Portstewart tram No. 1 as above is correct. Now we see what they meant by "invisible green"; this thing is preserved in correct BNCR livery and lining. Comparison with the bright green in the one above shows how crassly wrong the Cultra engine is; they have the BCDR NO. 30 in a similar bright green - which it never carried. BCDR livery was almost as dark as BNCR - certainly a good shade darker than UTA green. BNCR carriage livery was a very dark maroon. mI'd need to check, but I think the lining was gold. You're right, Fry has nothing actually in BNCR livery.
The livery of the CIE brake van in Cultra is wrong too, on a number of counts, as are some other things too. Whitehead is another offender, and so on. Even 800 "Maedb" is wrong; it's been given "G S" letters on its tender in there, when it's in full Inchicore-applied standard CIE 1950s passenger loco / bus green. GSR green was nothing like that.
However....... the good thing about our hobby is our diverse interests and ability to amiably discuss differing opinions. I am well known for an interest in liveries, so while I fully accept and fully respect any opinion which says "who cares about the livery"; fair enough - but I do, and it really irritates me to see something wrong, especially when it could so very easily have been done right in the first place!
Wow! You had me there, Rob - that is a VERY rare beast of a photo!