Short answer. Yes. The Civil Code makes non-collation the default only if the testator has not otherwise provided — so a will that expressly orders collation of a testamentary gift overrides that default, though the legitime must still remain unimpaired either way.
What the law says
Property left by will is not deemed subject to collation, if the testator has not otherwise provided, but the legitime shall in any case remain unimpaired.
Civil Code, Article 1063 — Property Left by Will. Read the full provision →
The default rule, and why it is only a default
Article 1063 states the ordinary rule: property left by will is not deemed subject to collation. But the article does not stop there — it immediately conditions that rule on if the testator has not otherwise provided. That phrase is the key to your situation. The non-collation rule is a default that applies in the absence of contrary instructions, not an absolute rule the testator is powerless to change.
A testator can expressly override the default
Because Article 1063 frames non-collation as conditional on the testator's silence, a will that explicitly directs that a testamentary gift be collated is doing exactly what the article contemplates: providing otherwise. Your parent's will saying the property should still be collated is not fighting against Article 1063 — it is exercising the very choice the article leaves open to the testator. The default yields to the testator's expressed intent.
The legitime is protected no matter what the will says
Whether or not the testator orders collation, Article 1063 adds one absolute limit: the legitime shall in any case remain unimpaired. This protection does not depend on whether the property was collated or not — it applies regardless. So while your parent could validly order collation of what he left you, that instruction cannot be used, directly or indirectly, to cut into the portion the law reserves for compulsory heirs as their legitime.
What collation actually does once ordered
Collation is the process of bringing a gift's value back into account when computing what each compulsory heir is entitled to receive from the estate, so that gifts given during the testator's lifetime or by will are weighed against the shares heirs ultimately receive. Ordering collation of your gift means its value gets factored into that computation alongside the rest of the estate, rather than being treated as entirely separate from the shares other heirs receive — while your own legitime, whatever the outcome of that computation, remains protected. This is why a testator's decision to order collation, rather than leaving the default non-collation rule in place, can meaningfully affect how the estate is ultimately divided among all the heirs.