I think with what little metal is around the top of the bolt area, that grooving would weaken it more. The 4 little holes near the bottom of the left side of the action should make little difference. the side mount is odd but very functional and also a stock factory option. the originals can be found and they do look much better than the two piece ones that are available.
Also a gunsmith that turns down a job that a customer wants done, because HE thinks the mount sucks...sure does not want business. IMHO