I watched the slightly cringeworthy Austrian crypto stamp discussion 2:54:00 onward.
There is no mention of five colours or rarities from the officials at all.
However they interview an Austrian customer (the girl Julia) and she said she would hope for more diversity in rarity. Something along the lines „five rare colours is nice [v1] but there is a lot potential for more variety in v2“. The interview seemed kinda staged, so we could hope that they included it to hint that there will be indeed a rare aspect like in cs1 again or even better.
But it doesn‘t seem certain to me, at all. So until we have confirmation on the chain or from officials, this is all just speculation.