I had been thinking a lot about the colors, and later I've found the answer for me

. I have a printed catalog of the same version as I own - It contains color samples. I won't bother with code numbers - I will simply compare the printed colour samples

. By the oldtimer qualification I can show this catalog and say, that I have an "official colour"..
Anyway I had a big problem also with my radiator - it was absolutely a rusty wreck. Its trademark was IPRA, so it is maybe the original one.. Unfortunately Betas have never been famous in Hungary, so I couldn't find any new radiators for my car here by any spare parts store. I've found the latest orderable radiators in the Valeo catalog from 2001. I asked some radiator restorator workshops about prices - they told me a minimum price of 300-400£ for a custom made version from Nissens material.
Later I visited a veteran radiator restorator near to my home. He's been working since 1990 only on radiators and is a professional. First I called him on phone, and was suprised. He said -" Well, if you have a Lancia Beta, then the radiator must be IPRA or Valeo". I watched it and he had right - even if he never restored any Beta radiators. He wanted to watch it live, so I visited him. At first sight he said, that it is very similar to the radiator of russian LADA 2105 (the older lada models based on Fiat 124 had a hole for crank - it was the main difference) He measured it and had right: all the dimensions were nearly the same - the maximum difference was ~1cm. Another difference was, that Lada radiator had a water-pour-in hole, and one of the two big snags was winding - and Beta had a small extra snag for the tube from the balance tank. The screw holes for the cooler motor were also not at the same places.
I asked someone who knows well the practise of the Hungarian oldtimer qualification, and he said, that the radiator is not the most important question, because many cars have problem with it, so maybe I can get the qualification also with a Lada radiator, if I won't say for them, that it is a Lada radiator and looks like the similar style as Beta radiator :-)
So after it I ordered a new modified custom radiator based on Lada 2105 radiator from this veteran restorator, and now I already have it at home. It costed together about 90£ for me (the radiator&modification) and looks great :-)