The trigger is unmarked.  Only the hammer and ser are marked "C".
I have replaced the following parts so far: US trigger, US magazine followers, and a US piston.  I am in the process of cleaning up the beat up Australian wood stock set I purchased and will be swapping it out soon.
 

Quick update:




Took the L1A1 out to the range today and shot it for the first time. Everything went well and it functioned fine, other than a misfeed on the last round of one of the mags. Had to set the gas setting on 3 to get it to eject and load the next round. Accuracy was not tested because I didn't have a sandbag.

Overall, I'm impressed and I like the wood stock set much better than the plastic Century set.






 

The wood looks so much better to my eye.   The later Marnyl was good stuff too.  Get one of each.    

Actually it's not that big a deal to have a second lower to swap them out, kind of like a suit with 2 pair of trousers.  I have 2 lowers for my century, one is the regular Marynl, the other is the extra short Arctic Marynl which is a better fit for me with a winter coat on.

Glad to hear it's up and running. That's the first test with these in my experience.

I'd be interested in hearing how the accuracy is when you get a chance to test it. They're not known for their accuracy but they are fun.