Need advice: Workshop wants me to claim insurance on an unendorsed engine swap. Is it a trap?

Hey guys, need some realistic advice on a sticky situation I'm in.

Long story short, I accidentally scraped a parked company car yesterday. I already went to the police station, made the report admitting 100% fault, and got my RM300 saman.

Here is my dilemma. I have a Comprehensive insurance policy (Lonpac). However, a few months ago I did an engine swap to another 1NZ engine (same exact engine model and CC). The catch is, the new engine is not endorsed yet—the engine serial number on my physical block doesn't match my insurance policy or logbook.

The workshop owner is heavily pushing me to file an Own Damage claim to fix my car's dented fender and scuffed bumper. He told me: "Don't worry, the CC is exactly the same, the engine looks identical, and the adjuster I know won't check the stamped serial number anyway."

I'm terrified that if I open an Own Damage claim, Lonpac's internal auditors or a strict adjuster will demand a clear photo of the engine number, catch the mismatch, void my entire policy for non-disclosure, and leave me personally liable to pay for the company car's third-party damages out of pocket.

My alternative is to completely drop the Own Damage claim, pay cash out of pocket to fix my own cosmetic damage, and just let the company car claim third-party against my insurance (since third-party claims usually don't involve the insurer inspecting the at-fault car's engine bay).

Has anyone here dealt with insurance claims on a same-CC unendorsed engine swap? Does the adjuster actually wipe down the block to check the stamped engine number for a minor accident, or is the workshop owner right that they turn a blind eye? Should I take the risk or just play it safe and pay cash?

Appreciate any insights!