[inglor_cz]

Yes, but you still need to design, assemble and test the particular equipment you want to use, unless you can do with off-the-shelf components.

And contemporary off-the-shelf components that perform the Sabatier process aren't probably meant to operate outside the Earth.

[SiempreViernes]

But this is merely testing, not any sort of large scale use of this equipment because, as you point out, they are not made to work on Earth.

[Fnords]

"you still need to design, assemble and test"

Not if NASA did that decades ago.

[gpm]

I certainly hope that there are technological improvements that we can take advantage of that have occurred in the past decades (in manufacturing, modeling of pressure vessels and chemical processes, etc).

Mass to mars is incredibly expensive, it's worth spending the time and money to optimize whatever equipment you are sending there.