One thing I do know: Google searches for "fiat Uno paint colour code" are a waste of time - more than half the hits relate to the late Lady Diana!
Your best bet is to find a good paint shop, which is where you will have to go for the paint anyway. They might have the small blue ICI books (one will be for FIAT) of paint colour samples with the names and numbers, though you might have some difficulty because there are often two or three 'variants' of the same colour. You really want the books rather than the computer lookup, since you don't have the sticker. But take the VIN with you just in case, because in theory there is a production record held by FIAT (in practice, who would have access to that?!)
You're right about the sticker - it should have been there, but replacement tailgates often don't have a sticker.
By the way, may I have a quick rant about my least-favourite paint code experience... You will be told at some stage that "ah, there's no point us mixing up the original paint recipe, because the paint on your car will have faded." This is sort-of true, but also completely irrelevant. Why? Because if you get some T-Cut and polish up your car, it will come back close to the original colour. Now see what happens if the paint shop had mixed-up paint to the 'faded' colour? You end up with part of the car being the wrong colour, no matter how much you polish it, and really annoyingly that part will of course have the newest paint.
My advice: always repaint with the original colour, and polish up the rest of the paint to match.
I have a red Uno sitting on my driveway which had the bonnet repainted. The tops of the front wings were 'feathered' to blend in the new paint. I was able to sand the feathered paint off and polish up the original red on the wings, doors, roof, and tailgate. The bonnet? That's been repainted in brown-coloured red, to match the other paint that had faded! Now I have to sand it and repaint with the correct colour...
Welcome to the forum, by the way!
-Alex
