Fritz Hansen Lily / Seagull / 3208? Rare?  

Hi. Lucky you! 
these chairs were designed in 1968 for the National Bank of Denmark. Later put into mass production in 1970. Arne Jacobsen died in 1971 so this is one of his last work. 
The model with armrest is 3208, the one without is 3108. The names you saw are nicknames so I would not really bother about them.

Yes, they are rare. They were produced only for 4 years, 1970-74. FH relaunched them in 2009. 

The fact you have one from 1977 is super odd. 

Thank you for this very interesting information DrPoulet.

Especially the one from 1977 is really odd indeed. Perhaps they kept selling them longer than they were produced, and the plastic cap was added in 1977? Just guessing here.

The white lacquer is showing a lot of small cracks due to old age. Probably not a good idea to strip the paint off these design icons I reckon?

My wife wants me to sell them because of the paint... 😒 But I really love them and want to keep them, especially now that I know a bit more about their history. Thanks again!

Don’t listen to your wife! 🙂 The paint cracks is patina and is desirable. Plus, there is zero chance you’ll find teak or rosewood underneath but rather some cheaper wood like beech and you’ll have to repaint them. A big work that will just reduce the value of your chairs.

The big watch out here is the sturdiness of the backrest. AJ chairs are fragile and are prone to crack where the backrest is attached to the seat.

Haha you're right, she will just have to accept that the chairs will remain a part of our lives! I also really like the paint to be honest. I don't know who I got it from, but I heard or read somewhere that age is the most precious thing a piece of furniture can have. Couldn't agree more, very much prefer these chairs over new ones.

I checked the backrests and the part where the backrest is attached to the seat and this all seems to be in pretty good condition. 

However, I noticed this nasty crack in one of the two plastic covers (see picture). Plastic becomes brittle over time so this is probably inevitable to a certain degree, but still it's a pity! Would this take away a lot from the 'value' of the chair?

Thanks again for the information, I am definitely starting to develop a love for design (history).

I don't think you should worry too much about a crack in a plastic cap. As long as the rest is fine and the cap is still there.

OK thanks, that's reassuring!