Is this partigyle brewing?

[sivdrinks]

I'm making a KBS clone soon and want to reuse the spent grains to get another 2.5/3 gallon batch of beer. I BIAB in a keggle, no sparge full volume. I'm trying to get an estimate on what the second beers OG will be. Most info I read on partigyle brewing is kinda backwards from what I'm doing, a larger batch first with an already estimated OG. Here's the recipe.

http://hopville.com/recipe/1355762/russian-imperial-stout-recipes/kbs