The recoil could pull/tear stitches, staples, etc...
If you're just sighting, why not get a good rifle rest and sight it in that way? My dad had open heart and was up and around 3 days later...but not healed. I would say based on my experience and medical training you have at least 2-3 months before you should be shouldering a high powered rifle.
Get a good rest that you can clamp the rifle to, bolt the rest to a table and you're set. Better sighting that way too...no worry about breathing and trigger pull. The rifle won't move