Hmm. High pitch in "A." That combo never occurred to me. It strikes me as strange that someone would play it in that configuration, and then tuck it away in an attic -- in the case -- without any other pieces.
But I suppose stranger things happen.
A side question: just how much music was written for a "high pitch in A" trumpet?
Here's a picture with the tuning slides pulled. You can't really tell in the picture, but the "top" slide is a different size than the "bottom" slide (I can't recall right now which is bigger). Also, the "crook" does not fit tightly without the "H" part. Pretty confusing...
Thanks for the responses!