Some do and some don't it seems. Depends on the base quality of the item.
Given that an inability to upgrade certain gear items seems like a common point of criticism across many reviews, it appears stats are mostly baked onto items and the ability to upgrade lowbie items whose appearance you like is quite limited.
This is particularly unfortunate considering a major theme in Cyberpunk is style over substance. Limited upgrade options and no transmog utility creates a situation where players are forced to choose substance over style, turning their edgerunner into a clown in the process.
(or lowering the difficulty mode, so cool-looking gear with bad stats can still suffice)
Why lower the difficulty, just up your own skills to compensate? Be diverse, adapt a little.
I plan to run around in a trenchcoat, if there even is one, if it effects my planned gunfighter build I will just have to improve my own stats to make up the gap.
The difference between one, two or 3 slots surely isn't going to be an absolute tragedy, besides I like a challenge anyway.
One reviewer has said all gear can be upgraded to Legendary, I have seen no evidence for or against at the moment though and I have watched a lot of leaks.
Decisions should have consequences, if a player wants to be a meta man, then it should maybe come at the price of looking like a clown.