I could be wrong and the above advice will get you an actual authoritative answer, but....
You're right you have a 58cm Z1 frame on that bike. I'm not sure how the serial number relates to the year. I don't have ready access to my frame. My guess is that your Z1 was originally purchased as a frameset, not a complete bike.
Back when I bought my Z frameset ('10 or '11) they sold three Z framesets, the ZA (aluminum), the ZC ("basic" CF) and the Z1 (upgraded/lighter CF). Now I believe they only sell a Z1 frameset.
Also in the past, if I'm not mistaken (could be, it's been a while) they didn't even sell a Z1 complete bike, the bikes ended at Z2 and the Z1 was reserved for frameset only.
Recently they do sell a Z1 complete bike, but I don't know when they started.
However, a Z1 would have higher end (I didn't say better, that's up to you) components than Sram Rival. It would be more likely to be Sram Red, Dura Ace or Shimano electronic. And most likely, Shimano, not Sram - again when I was shopping higher end Felts a few years ago, they didn't sell them with Sram. Again, I'm not saying better, Rival's good stuff, but wouldn't have been sold on a Z1 complete bike, I don't believe.
Anyway, regardless of whether it's a Z1 complete bike that was changed to Rival or a Z1 frameset that was built up with Rival, you have a top of the line, very nice, very lightweight frameset worthy of any rider and certainly worthy of any "upgrades" you care to put on it.
I absolutely love my Z bike (a ZC frameset, it was about 200 grams heavier and about $800 cheaper than the Z1 frameset the year I bought it... but I received an upgraded fork, the same as on the Z1 which greatly mitigated any differences) I have built it up with decent wheels and Sram Red.
Don't let anyone tell you that Z frames are "slow" because they're more relaxed designed. I can set my Z up very comfortably for my needs compared to my old Cannondale R2000 (CAAD7), and compared to the true racing bike, it's is a wonderful riding, fast bike. I can get as low as my body will allow, and it's very lightweight for the uphills, and very fast and stable on the downhills (my PR is ~50 mph on the Z, compared to not quite so fast on the Cannondale....which I don't even care to go any more). Difference is I'm just more comfortable and confident on the Z - can also ride a 60 miler faster because I just have less all around fatigue.
Z1, verrry nice!