It sounds like you're looking at a standard Riot Model 97, rather than a Trench Model, if it doesn't have the heat shield and bayonet lug. Look on the barrel and see what's stamped where the barrel meets the receiver. It should say what the choke was on the original configuration. If it says Full or Modified, it's a cut down gun, not an original Riot gun. Also, is this a solid frame or take down gun?
Depending on the age of the Model 97, it may be chambered for 2 5/8" shells with roll crimps, or 2 3/4" shells with roll crimps. If chambered for either of those, then it would need to be rechambered, or at least the forcing cone relieved. Only the later guns were chambered for star crimped 2 3/4" shells.
The early Model 97's, at least into the early 1930's, had forcing cones that were all over the place in length. They were apparently chambered by hand, and it depended on who chambered it and how industrious he was at the time. Some of mine were short chambered and some weren't.
You can tell if your gun needs to be rechambered two ways. The first, and best, is to take it to a gunsmith who works on shotguns and have him check the chamber with a gauge. Lacking this, you can fire a low power target load in it and check the mouth of the case. If the edges of the star crimp are shredded or beat up, then the chamber is too short and the mouth of the case is into the forcing cone and the shot is causing the damage to the case mouth, which also increases pressures. Increased pressure isn't a good thing in a gun around 100 years old.
For the most part, the Chinese parts won't interchange with an original Model 97 Winchester. The Chinese use a mixture of Metric and SAE parts in their guns. There have been efforts to get them to produce parts for original guns, but some parts just don't convert readily to Metric, i.e.: a 4x54 screw. The wood may interchange, but that's just a guess, since domestic replacement wood is available.
It's completely normal with the Model 97 to have to move the forearm slightly forward to open the action on an unfired gun with the hammer down. This tells you everything is matching up correctly. You can also push the action release button on the right side of the receiver when the hammer is back, which will allow you to open the action without lowering the hammer.
Hope this helps.
Fred