I've got one similar, 606XXX serial number. It was my first sax, had it for the best part of 30 years and kept it for sentimental reasons.
To be honest, they're not the greatest of saxes, made after Selmer bought the company. Yours (and mine) date from some time in the 1970s, by which time American saxes had gone from great to frankly pretty poor. However, they're reasonable enough student standard saxes, with a pretty OK tone. I had mine repadded about ten years ago, and it plays easily from top F down to bottom Bb. Sounds like yours has a catastrophic leak in the top stack. With a bit of luck it'll be something a decent repairer wll be able to fix quickly and cheaply. Then you'll have reasonable tenor to blast on. I found mine worked best with raucous high baffle mouthpieces. If not, I'd suggest not spending a fortune on it as the sax will never be worth a bundle.
Jon