Short answer - yes.
I'll quote the Tolkien Estate article on his invented languages:
Just as Tolkien’s Legendarium underwent decades of development and change both before and after the publication of The Lord of the Rings, Tolkien’s languages also underwent decades of elaboration, reconsideration, revision, and recapitulation throughout his lifetime. And also just as with the Legendarium, he never completed the languages; nor did he regard finality or fixedness in his languages as either necessary or even desirable goals. Nearly every occasion upon which Tolkien set to writing about or in one of his invented languages resulted in new invention, reconsideration, and change in the languages as they were then and previously conceived. Not even publication imposed fixedness on the languages, as shown by the changes Tolkien made to various Elvish texts in the second, revised edition of The Lord of the Rings, and by his own later reinterpretations of those texts in light of the conceptual alterations that arose in the languages after their publication.
The J.R.R. Tolkien Encyclopedia also states that Tolkien continued to develop and change his Elvish lexicon in successive versions throughout his life in accordance with changes in his linquistic aesthetic. Source
A couple of examples are mentioned here: http://folk.uib.no/hnohf/qlreview.htm such as the word "Vala" initially meaning "a happy one" but then changed to "Power" or "God".
Regarding Lord of the Rings, the writing of it actually served as a catalyst for revisiting and making changes and additions to the Elvish lexicon, given all the wealth of detail and history concerning the Second and Third Ages that this book introduced.