Similar to how with the Starter Pack the shield and bomb have a chance at a UV (which is where I got the idea).
I think all gear, bought with crowns from a Vendor or bought with tokens from Brinks should have the same chance at a UV as crafting. I just think it would be fair, if I'm collecting all these tokens to put towards this gear, I should have a chance at a UV from the get-go.
This is coming from a guy who would like to work on a UV for the new thorn shield, but would like 4 chances at a UV instead of 3 going from 2** to 5*****
I'd definitely say yes for items obtained with tokens - there's a chance some people who have accumulated a large number of tokens may do some "ragebuying" to get UV's, but this'll sink any surplus of tokens pretty quickly.
Not sure about items purchased for crowns - I don't *think* "ragebuying" would be cheaper than ragecrafting for any item, but I haven't researched all the mats used in crafting the items the vendors sell. And I'm not all that certain that ragebuying would be a bad thing - if nothing else, it'd take large chunks of crowns out of the game...