York sousamaphone help needed!!!

[Mattlionel]

Hi I know nothing about tuba I play sax anyways inherited this York silver grandrapids tuba...doesn't seem to be the monster version..valves move any idea as to value?? The store offered 700 which was more then I thought it was worth so got suspicious....I believe it's bbflat

[lowtones425]

Pictures would be helpful...

Is it a tuba or sousaphone?

[Mattlionel]

Sousaphone 89234 serial