The so-called Constitutional option is a farce. Filibustering is just as constitutional as passing a Senate rule forbidding it is. They are both Constitutional options. There are other stories of nominees being delayed over a year because the Senate didn't like them. It's all legal, and it's all been done since the beginning. The feckless GOP is hoodwinking its own by pretending they are victims. They're not victims; they're frauds.
Nope, the Senate originally did not allow the filibuster. Four Senators (of 24?) could 'call the question' ( or 'call the previous question').
From the Journal of William Maclay, United States Senator from Pennsylvania, 1789-1791 , who was on the committee that wrote the rules of the first Senate: "Rule 7 [8]. In case of a debate becoming tedious, four Senators may call for the question; or the same number may at any time move for the previous question, viz, "Shall the main question now be put?" "
IE: it ended the debate if passed by a simple majority, and whatever was before the Senate would then be voted on.
The first attempt to "filibuster" a presidential nominee was on January 16 1792. There was an attempt to block consideration of the nomination of William Short as minister to the Hague in which the tie vote was broken by VP John Adams:
"The numbers being equal, the previous question was by the Vice-President determined in the affirmative. On the question to advise and consent to the appointment of William Short, of Virginia, now Chargé des Affaires of the United States, at Paris, to be Minister resident for the United States, at the Hague, as nominated in the message of the 22d December; "
Years later (1797) an attempt was made to block President Adams nomination of his son John Quincy to be minister to Prussia which was also ended by "calling the question".
I do doubt the Senate would restore it's original rules without extraordinary influence being brought to bear upon it.