It depends on how you define "concept" and "meaning". Which is to say, neither term is uncontroversially and unambiguously defined, even limiting the discussion to technical linguistic usage. (Or, "especially if you limit the inquiry to technical linguistic usage"). The most difficult part is figuring out what a "concept" is. We clearly have to avoid the senses exemplified in expressions like "I really like open concept" (home renovation), "Whadda concept!" (general talk). The Oxford Dictionaries philosophical definition is a reasonable definition (not theory of) "concept".
An idea or mental image which corresponds to some distinct entity or
class of entities, or to its essential features, or determines the
application of a term (especially a predicate), and thus plays a part
in the use of reason or language.
To get a deeper understanding of "concept", I would recommend a scholarly philosophical treatment of the term, such as the Standford Encyclopedia entry, especially section 1 on the ontology of concepts.
One would need to inspect the linguistic literature to see how the word "concept" is used, qua technical term. The Routledge Dictionary of Language and Linguistics punts, by pointing "concept" to "notion" which it defines as
Idea which is conceived through abstraction and through which objects
or states of affairs are classified on the basis of particular
characteristics and/or relations. Notions are represented by
terms. They can be defined like sets: (a) extensionally, by an
inventory of the objects that fall under a particular concept;
and (b) intensionally, by indication of their specific
components. The current equating of ‘notion’ with ‘meaning’ or
with Frege’s ‘sense’ (‘Sinn’) rests upon an intensional
definition of ‘notion.’ (also definition, intension)
That constitutes one vote that meaning and concept are the same, if we assume that concept and notion are indeed equivalent.
I do not think that "concept" is a technical term in linguistics, any more than "sound" is one. To determine whether "concept" and "meaning" are really the same thing, one would devise substitution frames to see if the terms are interchangeable. The syntax of the terms is different, of course: you would say something like "The concept of 'liberty' refers to ...", but "The meaning of 'liberty' is...". At the level of sentences, it is clearest that meaning and concept are not the same. You can say "The meaning of 'All of the arrows didn't hit the target' is that ...", but you would not say "The concept 'All of the arrows didn't hit the target' refers to...", because a sentence is not / does not (re)present a concept, it represents a proposition.
"Keys are on the floor" is ungrammatical, but "The keys are on the floor" does not contain any pronouns. "On the floor" has a meaning, which relies on at least two concepts (the relational one "on" and the referential one "floor"). The relational concept behind "on" is a specific kind of positional concept, which includes "in", "by", "under" and so on. "On the floor" does not describe the concept "position", it exemplifies one kind of position relationship. "Cat ate food" is ungrammatical (unless this is the person "Catherine"), but "The cat ate food" is okay. It is a proposition which relies on at least three concepts, namely "cat", "food" and the action "eating".