You can do all the mods you want, just make sure you are compliant. When ordering up your parts it is very important to know if you have a stamped or milled receiver,and whether your receiver is straight or angled - you need to take the butthole stock off and look at the rear of the receiver. Try ironwooddesigns.com for wood furniture.
BTW do yourself a huge favor and add a red dot optic, it makes ALL the difference. The Choate (fiberforce) stock shown on my gun is ban compliant and a big improvement over the Chinese wood.
Now, the rest of the bad news. Norinco made AK's have a thicker receiver, action block and barrel than east block AK's. Most of the quad rails on the net will not fit as the MAK barrel and other dimensions are too thick. Make sure before you order that the descripition says the parts will fit the MAK
has the quadrail for the thicker barrels. Just search the AK accessory selection. I have the UMG quad rail on my MAK 90: