Is $50 decent for used 15 lb tank/dual guage regulator/sanke tap?

I've been looking for a second regulator and CO2 tank (I currently have a 5 lb and dual gauge reg). I found a 15 lb tank on craigslist that came with a dual gauge regulator and sanke tap for $50.

I knew the setup was pretty old and would at least need a hydro test ($20 at South Jersey Welding for me) but it seemed like a pretty good deal. I also need to replace the sanke fittings. Did I just blow $50?

Follow-up questions:
The regulator gauges both read too low...is there an easy fix besides new gauges?

Apparently the 15 lb tank is pretty full. The last date I could find on it is from 1987...do I use the CO2 before exchanging it or exchange now just to be safe? I don't want the tank to a) explode on me or b) get sick/ruin my beer from old gas.

if theres no rust, i would certainly use the gas, it won;t go bad, only the tank would.
a tap these days is about 30, so its not a bad score!