You are confusing Imperial Grenadier, the title of the WW1 PG series proposed as a feedback title in 2006, with the April Fools Imperial Grenadier, the Invasion of Poland.
Titles in the "Imperial Grenadier" series:
1. August 1914
2. The Mouse That Roared
3. To Help With Spain
4. Fall of Empires
5. Edelweiss Division
6. Imperial Guard
7. Lawrence of Arabia
SGWPG titles
1. Land Cruisers
2. Imperial Marines
3. River Fleets.
Not to be A smart aleck.... but why is the series refered to as Infantry Attacks on the AP website? I am tracking Imperial Grenadier as the April fools joke that turned into the Second Great War Series.