A question for the knowledgeable whistlers out there: Did the Feadog Mk 1 come in both brass and nickel versions? I seem to have one of each, but I don’t remember reading that there was a nickel version. 
I don’t believe so - but I’ve been wrong before. I’ve only ever seen them in brass. If you post a pic, there are plenty of people here who could give you a better, more educated answer than mine, as to exactly what it is that you have.
Unfortunately I haven’t a clue about how to post a picture here. I have one on my Facebook page, but can’t seem to add it to my message here.
Posting pics to this forum is a closely guarded secret that we keep here https://forums.chiffandfipple.com/t/guide-to-posting-images/22873/1
You’re a lifesaver - it worked!
I’ve only ever seen them in brass.
Nevertheless, all feadóg models have always been available in both brass and nickel versions.
Maybe there ought to be a post your whistle photo day thread, and, in addition to the photo collections sticky thread already up top of this forum. Especially for the newer members.
Seeing whistle pics gets the juices flowing! 
Those are both Mark I Feadogs, if you had any doubt.