So I flew out to Gatwick with FR on Wednesday, back the same day, and both flights were on EI-FRF. This is an April 2016 delivery, complete with the Boeing Signature Interior, which is very nice (except for the very hard seats, but I'm guessing that's more FR than Boeing).
Anyway, when boarding, I noticed the landing lights embedded in the root of the leading edge. And they were different...what looked like an array of LEDs.
Fast forward to this evening, and an aircraft with very bright 'ultra-white' lighting was heading into BFS. A quick check on the web confirmed it was FR1137, operated by EI-FRF. Added to the landing lights, the strobes also seemed to be much sharper in intensity and on-off cycle...so again, likely LEDs.
Just trivia I know, but (for now) a way to spot a new 737 by night!
I don't think I've seen an Airbii with LEDs to date, although I think the 787 also features them.