Update on progress—and appreciation for the input:
Terry McGee wrote:
Be aware that in some pin-mounted flutes, the pin can only go in one way and must be tapped out the other way. You could test one of the removed pins to see if they are tapered or cylindrical. A drop of penetrating oil, alcohol, WD40 or anything else you have available applied to the pins at all four places and left for a while might help. Otherwise heat gently applied to the posts (if you can apply it safely) might also help.
I've now managed to remove all the pins and the keys. They are all straight rods with rounded over "heads" on one end. All the keyed holes are closed with sticky wax.
Steve Bliven wrote:
It appears that the instrument is in Eb based on the two upper notes (the ones that will sound) being a half tone above where they would be if it was in D. Overall length is ~263.5 mm and sounding length is ~276.25 mm (here in the US it's tough to find a ruler in mm...) It's also shorter in sounding length than one of Jem's plastic pics in D. Does this seem to fit with the Eb theory
Terry McGee wrote:
I think you've got your calculations wrong - the sounding length can't be greater than the overall length! This might help. A D piccolo can be expected to be 302-308 overall length and 252-258mm sounding length.
I did, indeed, flip the measurements.

With the keyed holes sealed, the instrument sounds in Eb.
The head cork was separated from the adjustment screw and was intruding into the embouchure hole. I pushed out the cork and reconnected it with the adjustment screw. The cork was wrapped with what appears to be cellophane tape but it fits tightly, can be moved and remains in place. Presently the second register is somewhat sharp of the lower register. Which way does the cork have to move to correct that?
Steve Bliven wrote:
The tuning slide is frozen in place. It appears to be brass (overladen with that green crud), both inner and outer sleeves. Any suggestions as to how to unfreeze the slide?
Terry McGee wrote:
If you have a metal rod that will go up inside the slide, heat it, insert it up the slide and run it around to heat the junction of the slides. It softens the breath condensate that is usually responsible for jamming slides. When you can feel some heat coming through, counter rotate the head and barrel back and forth and in and out to amplify any available movement. You might need to repeat the heat treatment.
I'll try that. Not sure I can rotate the parts with my fingers crossed but I'll try. At this point, there is no available movement at all. Hopefully the heat process will allow some.
Steve Bliven wrote:
And it needs re-padding. After reading
Jem's tutorial for anoia back in 2011, I'm pretty sure that I'm not ready to re-pad the little beast. So, I'd need to find someone to do that.
Terry McGee wrote:
Any woodwind repairer should be able to do this at least in theory.
I'll start with the local music store. They supply band instruments for the local schools and may have repairer contacts. One of the keys doesn't seem to cover the hole—I'm wondering if one of the posts might be out of alignment. Is that a thing? And is it a simple fix? If not, I may just leave that hole (G#) waxed and not bother with that key.
Terry McGee wrote:
If you can get it going as a keyless you can see if it's fun to play, and has plausible performance and intonation
It is working as a keyless. It's pretty tight fingering, tiny holes, and a very different embouchure that anything I've played previously so I'll have to hold off on the "fun to play" part. The intonation seems to be pretty good, given my bumbling about with the new situation.
And Dan A: I've given it a thorough look and can't find any maker's mark. But, other than the G# post issue and the frozen tuning slide, I don't see any damage.
Thanks and best wishes.
Steve