The barrel is already threaded, I see a muzzle nut.
Beware of the brakes on sale now, Romanian rifles have a different thread than most other AK rifles.
What you do now is find a US made red colored pistol grip, finish re-finishing the wood so it all matches (or buy a US made wood pistol grip, and refinish it to match the rest of the gun).
Then, put a SWIFT safety lever on it- or cut your current safety lever. What this means is that when your rifle's bolt is held open by a Yugoslavian mag, you can pull the bolt back a little and flip the lever up to hold it in place while you change mags. Then, when the new mag is in, pull the safety down and it releases the bolt. This can speed up mag changes.