Can i get the ruger mk III Standard modified for competition shooting.?

Question

or is it possible to put rail mounts for a red dot.

Answer 1

You won't have to be around competative shooting very long to find out who the gunsmiths are who can do waht you want.  Go to some matches and between matches, ask around and they will tell you who is doing what you want.  Do not take to just any gunsmith, be sure that he is someone who knows his stuff and is recommended by the people who shoot the guns.

Answer 2

yes and yes, there are a lot of options just find a good smith and ask.good luck.