Is the Non-Canonical Saying Shared by the Carpocratians and Clement of Alexandria (Str. 3.2,11) a Variant of Mark 10:17,18?

Let's recap what I discovered yesterday.  Clement and the Carpocratians shared a non-canonical gospel with Jesus announcing the words "Ego autem dico, non concupisces" (but I say unto you, do not lust...) The editors of the English translation of the Stromata seem to think that it is a variant of Matt 5:28 but this can't be because Clement cites the material correctly in Str. 3.2

And how can this man still be reckoned among our number when he openly abolishes both law and gospel by these words. The one says: "Thou shalt not commit adultery." The other says: "Everyone who looks lustfully has already committed adultery." The saying in the law, "Thou shalt not covet," lt shows that one God is proclaimed by law, prophets, and gospel; for it says: "Thou shalt not covet thy neighbour's wife."

Later in the same chapter Clement gets around to citing the saying from the shared non-canonical gospel:

If the adulteress and he who committed fornication with her are punished with death, clearly the command which says "Thou shalt not covet thy neighbour's wife" speaks of the Gentiles, in order that anyone who, as the law directs, abstains from his neighbour's wife and from his sister may hear clearly from the Lord, "But I say unto you, Thou shalt not lust." The addition of the word "I," however, shows the stricter force of the commandment, and that Carpocrates fights against God, and Epiphanes likewise.

And then later in Chapter Four of the same book:

The Lord has said: "But I say unto you, you shall not lust." How then can he live according to God's will who surrenders himself to every desire? And is a man to decide of his own free will that he can sin, and lay it down as a principle that one may commit adultery and revel in sin and break up other men's marriages, when we even take pity on others if they fall into sin against their will?

And then yet later again in Chapter Eleven of the same book:

Right from the beginning the law, as we have already said, lays down the command, "Thou shalt not covet thy neighbour's wife," long before the Lord's closely similar utterance in the New Testament, -- where the same idea is expressed in his own mouth: "You have heard that the law commanded, Thou shalt not commit adultery. But I say, Thou shalt not lust."

I am increasingly certain that disputed saying is actually a citation of Mark 10:17,18 which is rendered in the Diatessaron witnessed by Aphrahat the Persian Sage as:

"And again, regarding that rich [man] who came before our Lord, and said to him, 'What shall I do that I may inherit life eternal?'. Our Lord says to him, 'You shall not commit adultery ...'"

The parallels in the structure of the sayings are quite striking:

Aphrahates - "Our Lord says to him, 'You shall not commit adultery."

Clement - "from the Lord, 'But I say unto you, You shall not lust.'"