Help with identification and service

[floopsy]

just been given this Rolex Air king, i think its a genuine article because previous owner has had a for years and years.
its in quite poor condition and i would like to learn as much about it as possible if anyone could help with year, model etc
Then if anyone has any suggestions as the best way forward to get it serviced and looking as good as possible, i will keep this as it has great sentimental value to me.