Yes this is saying we need to watch out for false teaching . Namely those denied Jesus came in the flesh .
but Paul says Jesus only came "in the likeness of flesh"
Romans 8:3, “For God has done what the law, weakened by the flesh, could not do. By sending his own Son in the
likeness (#G3667) of sinful
flesh (#G4561) and for sin, he condemned sin in the flesh,”
#G4561 - sarx: flesh
Original Word: σάρξ, σαρκός, ἡ
Part of Speech: Noun, Feminine
Transliteration: sarx
Phonetic Spelling: (sarx)
Definition: flesh
Usage: flesh, body, human nature, materiality; kindred
#G3667 - homoióma: that which is made like (something), Original Word: ὁμοίωμα, ατος, τό, Part of Speech: Noun, Neuter, Transliteration: homoióma, Phonetic Spelling: (hom-oy'-o-mah), Definition: that which is made like (something)
Usage: (originally: a thing made like something else), a likeness, or rather: form; a similitude.
HELPS Word-studies
“likeness” is word #G3667 homoíōma (a neuter noun derived from homos, "the same") – properly, the same as; likeness, similitude (resemblance). #G3667 /homoíōma ("likeness, particular similarity") is a comparison used to increase understanding. 3667 /homoíōma ("resemblance") does not require one element of a comparison to be derived from the other; indeed, it can be wholly separate from it. Rather, #G3667 (homoíōma) refers to a basic analogy (resemblance), not an exact copy.
Thayer's Greek Lexicon
#G3667 - ὁμοίωμα, ὁμοιώματος, τό (ὁμοιόω), the Sept. for תְּמוּנָה, דְּמוּת, צֶלֶם, תַּבְנִית; properly, that which has been made after the likeness of something, hence,
a. a figure, image, likeness, representation: Psalm 105:20 (); 1 Macc. 3:48; of the image or shape of things seen in a vision, Revelation 9:7 (cf. Winer's Grammar, 604 (562)) (Ezekiel 1:5, 26, 28, etc. Plato, in Parmen., p. 132 d., calls finite things ὁμοιώματα, likenesses as it were, in which τά παραδειγματα, i. e. αἱ ἰδέαι or τά εἴδη, are expressed).
b. likeness i. e. resemblance (inasmuch as that appears in an image or figure), frequent such as amounts almost to equality or identity: τίνος, Romans 6:5; Romans 8:3 (on which see σάρξ, 3 at the end (cf. Weiss, Biblical Theol. etc. §§ 69 e. note, 78 c. note)); Philippians 2:7 (see μορφή); εἰκόνος, a likeness expressed by an image, i. e. an image, like, Romans 1:23; ἐπί τῷ ὁμοιώματι τῆς παραβάσεως Ἀδάμ, in the same manner in which Adam transgressed a command of God (see ἐπί, B. 2 a. εε.), Romans 5:14. Cf. the different views of this word set forth by Holsten, Zum Evangel. des Paulus u. Petrus, p. 437ff and (especially for examples) in the Jahrbüch. f. protest. Theol. for 1815, p. 451ff, and by Zeller, Zeitschr. f. wissensch. Theol. for 1870, p. 301ff. (Synonym: cf. εἰκών, at the end; Schmidt, chapter 191.)