The rear C1 and C2 sights are common around here. I have both lying around my shop, along with new lower receivers, and some new internal parts.
When the 8L C1's came into the country I received one that like new condition and was just test fired in the UK.
Sold it for three times what I paid for it and along with a new H&K Sub Cal kit I regret that move. I have lots of other FN's but haven't ran across another one.