help with dating a Panerai 50

[stusrt]

a local jeweler has a used panerai 50 for sale I am very interested in. Great price!

All the paperwork is included, it was purchased at Tourneau in 2004.

However, when I looked on the back, I could not find the letter to indicate year. I attached a picture from paneraisource.com I used for a reference. But this watch did not have the letter on back.

Should I be looking elsewhere? Warranty card?
Basically I am going to buy if it is a G, but not F (huge difference in production numbers between the 2 years)

thanks!