Gluing the bow up with the riser block on will make the center of the bow flat because the riser block will hold it flat.
The glue joint is what holds these bows in their respective form shape.
Glass bows are glued all together because the riser and form are pre-shaped before glue up.
Wood bows are different. When you would take that bow out of the form, it's going to look weird.
Here is my bow out of the form. Notice the curve in the riser section.
I trace that curve onto my riser block, then cut the riser block to the line and then glue the riser onto the bow blank.
Below is a riser blocked shaped and glued on the blank.