You could siphon loot from another area to include in the Vault. Or as I played it, the Vault other treasures were looted with Baraket. The gloves were left behind because didn't detect as magic, appearing as normal gauntlets (artifacts can be fickle like that). Allow the players to find a well hidden message in Thassalonian that suggests these gloves are more than they seem. This message was overlooked by the previous looting party. Gave my PCs a nice hook to investigate this interesting item.
I didn't do this as I feel it completely goes against the story as it was set-up. In the end I just put the rod and diamond dust in there too.
Part of the story as set up is that Roderic due to a combination of sheer luck and skill was able to get into the vault, but due to setting off the traps he had to flee and barely made it out with his life. Narrowly avoiding death made Roderic never want to enter the vault again and made it so he only took Baraket. This is also what the Ghost of Roderic told my players, albeit a lot less coherently.
The vault being difficult to open is important to the story, I know my players well enough that they will start asking difficult questions and will start a hunt to this "mysterious 3rd party" that was able to crack this difficult vault and looted it but did not take the artefact.
"ornate set of gauntlets made from noqual covered in hundreds of softly glowing Thassilonian runes.
What genius would be able to crack this vault and loot it yet would leave the set of gauntlet behind? Unless you'd want players to be really paranoid about the gauntlets, which mine would probably be so we'd lose a lot of gametime while they try to figure out what's with the "cursed" gauntlets .