Almost certainly it is in the old pitch rather than the modern A=440Hz. Sounds like a single row melodeon and if it's in tune with itself then have fun playing it. Many traditional tunes can be played on it (cajun, for example is played on a one row as are East Anglian tunes in the UK). If you can play a diatonic (not blues) harmonica you should be able to easily handle the treble side and if you can live with the occasional 'wrong' bases inherent in this instrument you should sound proficient quite quickly.