Curious what conspired with the OP's project. I too have an H-S stock that i had the same thoughts about, not grinding out any of the original aluminum block surface in my case but just bedding the lug recess.
My gun sits upside down as we speak in the curing stage.
While i was already bedding the lug recess, i decided to scratch up the front block's surface and apply the Devcon there as well, why not, its right next to the lug recess i was bedding- might as well. I used the smallest carving attachment of my Dremel set at a slow speed and let it bounce up and down on the entire block surface to rough the aluminum up real good. Then, i went on and drilled some 1/16" shallow dimples evenly spread across the surface of the same area. Since i still want to be in contact with the original surface up front and did not bed the rear at all, i torqued the action to the stock immediately before the Devcon had time to begin to cure.
I dont believe i altered the original state too much and hope this will benefit to further support and stabilize my action in this cool new stock i bought.