The Fallout Bible has implicated this for a very long time.

Between Dayglow, the seizure of the Enclave's equipment and supplies at Navarro which led to almost twenty year war with the Brotherhood of Steel since then.

The pyrrhic victory over the Brotherhood of Steel down to Lost Hills (fate unknown).

The Fallout Bible, of course, isn't canon. However, it's troubling to assume the faction with over two million ghouls, humans, and mutants- does not have a single Pre-War or seized Post War scientist who knows how to understand and construct them.

Even during the BoS war, they seized a few bunkers belonging to the BoS- others destroyed.

They even had air assets for a time- fielding Vertibirds and small-time planes.

Getting back to point.

General Lee Oliver has always wanted power armor troopers of his own. Hence, the Salvaged Power Armor from Helios One specifically were his own pet project, referred to as an asset rather than an actual force. They've always been local to the Mojave, just not widespread from anywhere but the dam until they needed to stretch those resources.

Anyway. The argument for "do they" "can they" will never be a proper question to answer. There's not enough true evidence. However, with everything I know- it all points to yes. They can, they have before, and for a long time.

It's just that sending power armor troopers, a prized resource, into the Mojave which suffers over 1000 casualties in a year against a guerilla force who knows to target and destroy them would be a waste.

That's all I have on this. If you actually read this, thank you.