mudd turtle,
will try to answer your ques, but this gun is still new to me, and dont understand the manual in russian.
scope mount came with gun, added my own rings to suit the scope height, mediums i think.
taking out the bolt is easy, pull back on the bolt a bit, and pull up on the big pin at the rear of the bolt and the bolt slides out.
havent tried a bore guide, but being a "bolt" any 22 mag bore guide should work, tho' havent tried one. i just use an otis cable thingee
mine is the .22mag and is the best mag shooter i have owned. super accurate to 100 yds so far, with an assortment of ammo, and am looking to shoot at 125 / 150 yds. am very happy with my russian "girlfriend". now if she could cook.............lol.
get out and take yours out for a spin, am sure you'll like it.