First thing is... I have both the 228 and the NP-34. I am not sure the NP-34 grip screws are the same. Does anyone know for sure? If not, I could take the grips off my NP-34 and compare the screws to some of the SIG screws I have. My thought is that the Norinco ones are a little smaller - but that could just be perception. The way that the threading is put into the Norinco frame
is different from the way it is done on SIGs. It looks like a brass insert in the aluminum frame:
I got some extra factory 228 grips from Numrich, back before ordering parts from the States went sidways. I think they will still send them to you, but they tack on $20, or something like that, to Canadian orders as some sort of export processing fee. So order some other stuff with the grips to spread out the pain a bit. You can get the grips screws there as well. Just google the name "Numrich". Just keep in mind their prices are known to be high.
Unless something has changed (for the better) since last Fall, Brownells will not ship any SIG parts to Canada (or many other firearms parts). I would love to hear that they are shipping again (as Brownells is the best parts place by a wide margin), but I had three orders cancelled by them last Fall until I finally accepted the new state of affairs.
If you look on the Questar page you will see that they now have individual grip screws for 4.99 each:
https://shopquestar.com/shopping65/shopexd.asp?id=845&bc=no
They also have the parts kits for SIG.
https://shopquestar.com/shopping65/shopexd.asp?id=525&bc=no
If NP-34 grips screws are interchangeable with SIG, the parts will work on your NP-34 (other than maybe the "new style" trigger bar return spring. Also the firing pin positioning pin has no application in a non-milled slide like a 228 or NP-34). Parts kit is 39.99. This is a pricey way of doing it, but it is all in Canada and you get an excuse to change your recoil spring... or have a spare for later. If it is $20.00 for 4 grip screws, maybe another $20.00 is not bad for a spare recoil spring, and the springs for the de-cocker, slide stop, and trigger bar.
If you want Hogue 228/229 grips, these should be easy to find. My local shop (Reliable) seems to always have them in stock. You can also order them from Dlask or many other sellers, as has been noted above.
Finally, you could try ordering individual SIG parts from the distributor through your local shop... or any shop. Shooting Edge is likely the best bet here if your local shop isn't enthusiastic about ordering small parts (as many of them see to be).
Besides, maybe I can fool a few more people into thinking it's a real SiG if they see the logo on the grips. 
