No. Not true. Once again, here’s the canon:
Can. 1060 Marriage possesses the favor of law; therefore, in a case of doubt, the validity of a marriage must be upheld until the contrary is proven.
In the case of a Catholic who marries in a civil-only ceremony without any kind of dispensation, the standard for proving that it was invalid is a rather easy one to meet. It is a short process to declare it null. But that is not at all the same thing as saying that it “does not enjoy the favor of the law.” Please see canon 1060.
Here’s a link to a petition for declaration of nullity on the grounds of lack of canonical form. Take a look at it.
archny.org/media/files/Petition%20Declaration-of%20Nullity-2008.pdf
The marriage (attempt-at) has to be formally declared null by the bishop or his delegate. Who that delegate may be, can and does vary, that’s not the point. But a formal declaration is necessary.