Gents:
If I may step in here.
I will say, that I have not seen this particular guy up close perosnally, I do know that that specs are pretty well the same for Late generation Norinco guns I have worked on.
The 14" barrel that I have seen are very nice and have the forcing cones done. As a result, they actually have a choke slightly more open than IC, and actually shot really well. This was a fact born out by the many conversations I had with Brobee, the originator of the CQB 870, and field testing.
However I to was interested in have chokes installed. The barrel walls are just to thin to have the barrel machined for chokes. If you can get you hands on a Dlask, or a real remington in the same/similar length thos will allo choke installation.
PaveHammer:
BBB and I discussed gun similarities at length for the standard models, and they were pretty much the same. Your best bet is to simply try it.
One word of caution. The forend tubes on the Grizzlies are slightly thicker thant the standard Remington ones, so if you want a remington forend to fit you will have to open it up slightly, and there after will only work on Grizly guns.
Hope that helps.
regards
AbH