Here is an exerpt from the RC Catechism
1127 Celebrated worthily in faith, the sacraments confer the grace that they signify.48 They are efficacious because in them Christ himself is at work: it is he who baptizes, he who acts in his sacraments in order to communicate the grace that each sacrament signifies. The Father always hears the prayer of his Son's Church which, in the epiclesis of each sacrament, expresses her faith in the power of the Spirit. As fire transforms into itself everything it touches, so the Holy Spirit transforms into the divine life whatever is subjected to his power.
1128 This is the meaning of the Church's affirmation49 that the sacraments act ex opere operato (literally: "by the very fact of the action's being performed"), i.e., by virtue of the saving work of Christ, accomplished once for all. It follows that "the sacrament is not wrought by the righteousness of either the celebrant or the recipient, but by the power of God."50 From the moment that a sacrament is celebrated in accordance with the intention of the Church, the power of Christ and his Spirit acts in and through it, independently of the personal holiness of the minister. Nevertheless, the fruits of the sacraments also depend on the disposition of the one who receives them.
1129 The Church affirms that for believers the sacraments of the New Covenant are necessary for salvation.51 "Sacramental grace" is the grace of the Holy Spirit, given by Christ and proper to each sacrament. The Spirit heals and transforms those who receive him by conforming them to the Son of God. The fruit of the sacramental life is that the Spirit of adoption makes the faithful partakers in the divine nature52 by uniting them in a living union with the only Son, the Savior.
Contrast this now from Luther's Small Catechism
How can bodily eating and drinking do such great things?
It is not the eating and drinking, indeed, that does them, but the words which stand here, namely: Given, and shed for you, for the remission of sins. Which words are, beside the bodily eating and drinking, as the chief thing in the Sacrament; and he that believes these words has what they say and express, namely, the forgiveness of sins.
Who, then, receives such Sacrament worthily?
Fasting and bodily preparation is, indeed, a fine outward training; but he is truly worthy and well prepared who has faith in these words: Given, and shed for you, for the remission of sins.
But he that does not believe these words, or doubts, is unworthy and unfit; for the words For you require altogether believing hearts.
As can be seen Luther, was quite precise as to where faith is directed. Whereas in the RC, faith is not defined and is rather vague, which allows for wiggle room in 1128. In 1128, there is the "nevertheless" clause which is confusing, because on the one hand it does not depend on the rigteousness of the recipient yet it depends on his disposition. If the RC does not object any longer to Luther's catechism, perhaps they have reformed themselves in this area and conceded they were wrong. Similarly in in 1129, the sacraments (and the RCs have more than 2 to 3 , I remember 7) are necessary for salvation. My Reformed brothers do have the right to be alarmed at such a talk. In fact the Apology registered these protests (just examples)...
III. 155 Just as,therefore, the Lord's Supper does not justify us ex opere operato, without faith, so alms do not
justify us without faith, ex opere operato.
III. 165 In this manner they also distorted the Sacraments, and most especially the Mass, through which
they seek ex opere operato righteousness, grace, and salvation.
XII. 11 They falsely assert that the Sacrament itselfconfers grace ex opere operato, without a good disposition on the part of the one using it; no mention is made of faith apprehending the absolution and consoling the conscience.
1128 is now a compliance to XII. 11 but again, there is no official definition of what that "disposition" is supposed to be, you may correct me if I miss such definition or clarification in the RC Catechism. When I contemplate that section of the RC Catechism I quoted, I come out confused. Somehow I can not help but think of double talk and I mean no disrespect, just an honest frank opinion. It seems such wording allows the RC to say -- we have not changed since the old terms are there, ie. justifying ex opere operato, and in the other sense, they can say - they have changed since they added more clarifications on the teaching that sounds Lutheran.
In logic, we have a maxim that says, from a contradiction you can prove anything. That is right, you can prove anything you like under the sun.
In summary, Lutherans do not believe in ex opere operato on sacraments. I hope my Reformed friends take note of that.