In removing the original Hitachi I noted the mounting saddle  and associated bolts lacking the standard Yanmar grey but coated instead with rusty corrosion. Wanting to dress things a bit in anticipation of the new alternator upgrade,  the mount will be cleaned and Rust-Oleum applied. Further, after having read of other people’s woes specific to alternator bracket failure, I want to inspect for cracks or metal fatigue.  For sure the bolts will be exchanged as a precaution. Witness this sad bolt in particular which suffered thread galling. I suspect that It is an SAE thread that wasn’t meant for the Metric hole tap or vice versa. I shall visit the parts bin and compare to find out more; but in either case the receiving threads in the engine block will need re-doing.