Yes, that is correct. Nouns do not carry the plural in Láadan; only verbs do. How many of something isn't Láadan's main focus, so it takes a little more work to talk about it.
The adjectival function is accomplished by pairing a stative verb (a verb that describes a state of being--as differentiated from a verb that describes an action) with a noun (a process known as relativizing) by the mechanism of attaching the relativizing prefix "wo-" to both. As you noted, we can indicate that there is more than one of the noun by pluralizing the relativized verb. Since the plural prefix "me-" is always the final thing added to any verb, it will appear at the very front of the plural relativized verb.
So: "Bíi yod le yuth wa." (I eat a fruit/some fruits.)
And: "Bíi yod le woliyen woyuth wa." (I eat a green fruit.)
And: "Bíi yod le mewoliyen woyuth wa." (I eat some green fruits.)
If there isn't a verb associated with the noun we want to make plural, we can use a Quantifier or a Number. Quantifiers are postpositional (that is, they occur immediately following the case phrase that is to be modified). There are several of them: "nedebe" (few/several/2-5); "menedebe" (many/6+); woho (all/every); waha (any). Numbers are used in the same way grammatically; there are, of course an infinite number of numbers.
So: "Bíi yod le yuth nedebe wa." (I eat several fruits.)
Or: "Bíi yod le yuth menedebe wa." (I eat many fruits.)
Or: "Bíi yod le yuth woho wa." (I eat all fruits.)
Or: "Bíi yod le yuth waha wa." (I eat any fruit.)
Or: "Bíi yod le yuth shin wa." (I eat two fruits.)
And you can combine these functional bits to make the plural relativized verb more specific.
So: "Bíi yod le mewoliyen woyuth shin wa." (I eat two green fruits.)
Or: "Bíi yod le mewoliyen woyuth waha wa." (I eat any green fruits.)
And now that that's all as clear as mud. I'll take my leave. If I've left questions unanswered, just ask.