Thanks. Seems like I have a MK1, based on the comments here and this former thread (although there’s no remaining decal at the bottom). I tried it in the Killarney head and it was a bit too big—would require some sanding down to fit. But a new Feadog would be worth the experiment…
Best wishes.
Steve
I can fit my MK.1 (confirmed) body perfectly in the Killarney head without sanding it.
I’ll post a picture on Sunday when I am back from Holiday
Would wrapping clear tape around bell end of whistle help/hurt the sound? Stabilize/strengthen. I’m thinking if the Mark I had a sticker there maybe it was more than decoration. Some of the less expensive whistle tubes vibrate (for me), or is that a desired effect for sound?
I might have to try the brass tube on the Killarney whistle.
Snake oil!
What about a Generation Eb body?
I have several Generation D bodies and I discovered that they were of differing diameters. Some were too big for the Killarney head, but one fit perfectly.
That has absolutely zero bearing on the sound. Unlike wooden stringed instruments, where the top of the instrument vibrates as part of the sound production, in whistles and other wind instruments it is the column of air inside the tube that produces the sound. The material doesn’t vibrate to produce sound in whistles.
The sticker was for decoration.
Well, you only need a whistle and some tape to find out. 
A great disenchantment for those in search of a “woody” sounding whistle, or those claiming that nickel plaited tubes make for a “brighter” tone! 
However, I would think that the air column does cause the tube to vibrate, which in turn might affect the wave form of that column. Just theoretical speculation though. I didn’t notice any effect by taping the tube anyway.
I remember a few people wrapping coloured tape around the top end of the tube because they had seen that some member of the Chieftains did that during the seventies.
Must work on flutes.
That’s good enough for me.
I didn’t notice any big change in sound either.
Often in whistles that are available in multiple materials such as aluminium/nickel/brass etc there is a difference in sound between the tubes of different materials (generations, burkes, etc.). However, the wall thickness is different for each of the materials. Brass Burkes have thinner walls, nickel generation tubes have nickel plating over the brass, etc.. which accounts for the difference in sound between the different materials. Plus, I am sure that corrosion on brass must have some bearing on the sound of a whistle, but again, this is changing the space in which the column of air resides, rather than the material itself having any bearing.
On the topic of brass bodies- I tried fitting a modern Feadog body onto my Killarney, wouldn’t fit. Although, the part of the body where the head attaches on the feadog is ever so slightly flared out on a teeny portion of the end of the tube, which might be the reason why. Going to try sandpaper…