Well I looked in both of my Jane's, 71-72 and 97-98. It could of course be more recent than the latter. In the latter, 97-98, I found two Russian river patrol type that resemble your model, but are certainly not spot on. Both classes mounted a forward tank turret, one a 3" and the other a 155mm. Your model certainly appears to sport a tank turret. Both also sported the rather unique railing running along the chine, as does your model.The super structures are vaguely similar, but again, not spot on.I found no river patrol craft listed in the 71-72 edition of Jane's. The dimensions were 140-180 ft long with beams of 20-30 ft respectively. The two I found were the YAZ(Slepen) Type 1208 class and the Vosh(Moskit) Type 1248 Class. My suspicion, and it is only that, is that yours is a scratch built(well built), although it could be an Eastern kit. It has some hall marks that point to a more modern build, rather than earlier.Not having anymore info makes it a good exercise in guesswork. Sorry I could not be more helpful.