Yes, in speech, these two sentences are perfectly normal and acceptable. For example, something like this:
A: さとうさんは？ (where is Sato?)
B: さとうさんは じむしょ (He is in the office)
Since you are feeling a little strange about this, let's see if I can help you make sense of it.
In every language, not just Japanese, it's quite common to omit stuff that are "obvious" given the context. In English, the response could be just "lunch," for example, omitting a subject and a verb.
In English, it's particles that glues a phrase like "in the office" to the rest of the sentence, so you can't omit that glue without making people feel like something is off balance. In an equivalent Japanese sentence (じむしょにいます), a particle "に" comes after the noun to connect the verb. So if you are omitting the verb (which is common in English, too), then it feels right to remove the particle as well.
The trailing "です" in your example is a different particle added back in to make the speech a little more polite. So in order to explain what's going on, I removed it from my example, and it's still perfectly acceptable speech, though it's a little blunt.