Not until today this came to my mind. The Enclave clearly sees no use to Vault Dwellers except testing their limits and then killing them, yet every civilian in the Oil Rig, with exception of government personnel, wear vault suits without numbers just like in Vault City.
Are these people really from a vault or did they just include those suits because pre-war outfits are perhaps in not that good condition after almost 200 years?

If I am correct, vault uniforms don't really degrade, unlike most pre-war clothing. That's probably why they wear them, they are built to last

But why Vault suits? Why those colors? It may be part of Enclave propaganda aimed at Vault 13 people though.. But I see not big reason not to color them black and gray as Enclave armors are.

Recycle templete

I'm guessing that's it. After all, remember how long the Vault Dweller's suit lasted in the Temple of Trials...

Maybe it's because high-ranking Vault-Tec officials were part of the shadow group that formed the Enclave?

Well if it's not broke why fix it....plus if you look at world history, many armies used the WW2 pattern British Battledress(with some modifications), up until the 1960's, so it wouldn't surprise me that the Enclave would use the Vault suits as standard issue clothing.

Since there is a large quantity of them, they would be easy to repair with other suits that could be used to patch the others.

Maybe all those stocks from the vaults that the intro suggests the Enclave was "visiting"? Or maybe the production lead had a deadline not involving variety?

In away the Oil Rig was like a Vault. Not everyone there was to have PA. The people that went to the Oil Rig before the War also brought family. People have lived on the Rig for Generations. It's clear that the Rig would need all the things a Vault would need. It even had a Geck. Did the Enclave get it from another Vault or was it always on the Rig? I don't know. Simple explanation for the Vault suits with no number is. They needed alot of clothing for generations of people, they already had contracts with people to make the Vault suits. So they just said "make us X amount of Vault suits." Cheap and easy way to solve the clothing issue for the Rig.

The impression I've had from playing through the Fallout series, or at least most of it, is that the Vaults were designed first and foremost as an experiment. Certain Vaults opened up almost immediately following the drop of the bombs while others stayed locked for a very, very long time (in the span of several human generations at the very least). The Enclave, on the other hand, was the remnants of the United States government, select troops, and whoever else they chose to invite into their sanctuaries.

Point being, the government (Envlave) seems to have been heavily involved with the contracting of Vault-Tec in the production of the Vault fallout shelters, as well as all things included with the Vaults. That being the case, it would not be surprising if they contracted them for other things, especially in the context of the Vaults being huge experiments. As part of the preparation of the Vaults for the coming nuclear bombs, the Enclave likely began to set up their own shelters. It is generally easier and cheaper to deal with one contractor, rather than many. Of course, that doesn't prevent the contractor from sub-dividing the work order and sending some off to other companies/factories.

Well for starters, Vault Tec was more or less The Enclaves public face. If I recall, Vault Tec was actually founded by the Enclaves key members. As to Vault suits. The Oil Rig is for all intents and purposes a Vault. No one except soldiers or military personnel leave the rig, they are all pale (Like a Vault resident would be) and wear durable jumpsuits. I mean heck, look at the crap The Vault Dweller went through, and his suit stood to the tests of two wanderers journeys.

If a vault suit goes through two heroes and is still in working condition, especially considering they're 80 years apart, you can't say much other than "Durable!"

Odds are BioWare may have taken a shortcut on the graphics for these minor NPCs when they did Fallout 2, seeing as the objective was to make this Oil rig Go booom, along with President Richardson, this and the fact that they seemd to have turned off some features if one chose the "Continue Playing" option.

Black Isle, not Bioware.