do they have some of the big fibreglass hulled minehunting types seen in EU navies ?

Yes, Projekt 12650 (NATO code-Sonya) is 450 ton minhunter with wood/fibreglass hull. Also a couple of larger Projekt 12660 (Gorya) – 950 tons, fibreglass hull.
Bryan, the Gatling gun on smaller vessels like Projekt 10750 and 12655 is designed AK-306, it’s light-weight version of AK-630 with only optical guidance.