Sorry, forgot about this.
Let's look at it this way: In most scenarios, even if the data of Pokémon is changed/modified, the PID will remain intact, as it is used for shiny determination. (let's say it'll be used as a sprite for a museum painting, for example).
Additionally, prior to Gen 6, the PID is the key used the encrypt the Pokemon's data. Meaning as long as they store the Pokémon somewhere, whether encrypted or decrypted, searching the PID will result in some hits.
Now, I used HOF extractor to see what the PID is. Then, I searched your entire save (note the values I used accounted for endianness, so every 2-byte word is swapped; example 1W 2X 3Y 4Z => 4Z 3Y 2X 1W)
I found exactly two hits. These hits are both the HOF data, one for main save, one for backup save (yes, a single Gen 5 save contains a main and a backup)
In conclusion, as expected, besides the HOF data your Reshiram data does not exist in your save.
So back to the drawing board, and create the IVs yourself.