Thank you for the extra information Cagney. I appreciate you taking the time to help as I have absolutely zero, nothing on American glass. I've read online as much as possible but that description you've quoted re the paleness of the amber really helps.
The different furnaces is interesting. The glass on this bowl just looks old and has some tiny specks and a stone in. Would that happen with a gas furnace? I don't really know how much cleaner or not they were or whether they had an impact on the quality of the glass.
Another question - they moved to Toledo in 1888 and continued production of Amberina and recorded between 1889 and 1891 apparently 200 batches (New England Pomona (1885–1887): Lead Analysis as a Study Tool, Beatrice Scheer Smith). Would they have been using gas furnaces at that point or was it later in the Libbey history when they were used.
I suppose I'm looking at the shape and the glass quality re the striations and seeds/stone and just thinking it feels like Victorian glass, and also I can't see this being particularly 'fashionable' in 1917 when they 're-issued'.
The only other question about Libbey v NEG is that if it were Libbey wouldn't it have been marked, as opposed to NEG which would have just had a label? Or was it only the re-issued 1917 Amberina that was marked Libbey?
Would the Amberina they produced between 1889 and 1891 not have been marked?
Having read about their Pomona glass recipes and the research that has gone into the lead quantity for that (New England Pomona (1885–1887): Lead Analysis as a Study Tool, Beatrice Scheer Smith) and taking into consideration the cost of experimenting with colloidal gold I can quite see that they would just replicate the original recipe given they knew it worked.
I still have the issue of not being able to match the shape or the hand crimped bowl rim though even if it is accepted a) that the very pale peachy amber base is right and b) that it is heat treated fuchsia.
I took my photos in daylight because the ones I've seen online show how the fuchsia looks under lighting but in daylight all glass looks a little different.
This is a fairly good/representative one under led lighting.
Yikes, so many questions and thoughts

apologies.