I suppose it's theoretically possible that this piano is indeed a low-pitch piano, but that would surprise me. I agree with Jim - I've never seen or heard of one, only read about them. The modern pitch reference of A=440Hz took hold around the turn of the century (1900), and by 1915-1920, all of the mainstream piano makers were using this pitch center. I play on a 1920 Mason&Hamlin grand that is certainly 440. Is is possible that the piano is in fact just so old that it won't hold a tuning at 440? That would seem more likely to me... I'm not sure how one would build a piano that couldn't be tuned up 10Hz. Of course, none of this helps you with your dilemma... I don't know of any way to lower the pitch of your tenor that much. If you can't get the piano somewhere close to 440, you may be out of luck.

Does the piano have sentimental value? If not, you should get rid of it. The piano, theoretically, can be tuned up to 440Hz, but it is a prolonged process - much more than tuning up a piano that has been at 440. Also, if the piano strings are old, you could have an issue with tensioning up all the strings (breakage). Depends on when it was dropped to 430. As far as dropping the tuning on your sax, you could try gutting out a mouthpiece to make the chamber larger, but there's no guarantee of how the intonation will fare. Have you tried pulling the neck out of the body some? That will get you a few cents, though maybe not consistently through the whole range of the horn.