Short answer. Yes. Under Article 161 of the Revised Penal Code, forging the Great Seal of the Government of the Philippines, or forging the signature or stamp of the Chief Executive — the President — is a crime, punished by reclusión temporal. It is treated as a grave offense against the State's authority.
What the law says
The penalty of reclusion temporal
Revised Penal Code, Article 161 — Counterfeiting The Great Seal. Read the full provision →
What the law says
any person who shall forge the Great Seal of the Government of the Philippine Islands or the signature or stamp of the Chief Executive
Revised Penal Code, Article 161 — Counterfeiting The Great Seal. Read the full provision →
What Article 161 punishes
Article 161 protects the highest symbols of state authority. It imposes The penalty of reclusion temporal upon any person who shall forge the Great Seal of the Government of the Philippine Islands or the signature or stamp of the Chief Executive. Three targets are named: the Great Seal of the Government, the signature of the Chief Executive, and the stamp of the Chief Executive. The "Chief Executive" is the President. Faking any of these is what the article forbids — the crime lies in the act of forging the seal, signature or stamp, not in what document it is placed upon.
Why it is punished so heavily
The penalty — reclusión temporal, a long prison term — reflects what is at stake. The Great Seal and the President's signature are how the State authenticates its most solemn acts. Forging them strikes at public faith in the official acts of government, which is why the law treats it far more severely than forging an ordinary private document. The article does not require that the forger actually deceived anyone or profited; the counterfeiting of the seal, signature or stamp is itself the completed offense, because the danger is to the integrity of official authority.
The forgery itself is the crime
Because Article 161 targets the making of a false seal, signature or stamp, the offense is complete once the counterfeit is produced, whether or not it is ever used. That distinguishes it from crimes that require a victim's loss. It also does not turn on the forger's rank or office — any person who forges these is covered. What matters is that the object forged is one the article names: the Great Seal of the Government, or the signature or stamp of the President. A convincing fake of any of them is enough.
What this article does not cover
Article 161 is confined to the Government's Great Seal and the President's signature and stamp. Forging the signature of some other official, or faking ordinary public or private documents, is dealt with by different provisions of the Code on falsification and forgery, which carry their own elements and penalties. Nor does this article address genuine documents that are merely misused; it is about counterfeiting the specific emblems of the Chief Executive and the State. Identifying exactly what was forged is therefore the first step in deciding whether this article, or another, applies.