No they are seen on certain years at certain factories. The riveted bayonet is a very late feature on n SKS, only seen after year 25 or so. For example in the arsenal /416\ photos below you can see that years 17 & 18 are screws vs 27, 28, & 29 which are all riveted. Obviously a change there. When you look at /26\ production, they used screws all through the entire (year 26) production run. I guess it just depende on what subcomponents the factory was set up to use.
One other thing: the removable riveted bayonet (like those seen in the SKS30) while prevalent in the commercial imports, I have not seen in any original military factory production run.
Year 17:
Year 18:
Year 27:
Year 28:
Year 29: