Update: 28th Nov As some of our more excitable readers are unable to distinguish between Spoiler and Rumour the rumour part has been removed and placed in the rumours section. That will teach me to be lazy :)
Update: 20:00 Before some of our more excitable readers explode let me try to explain some stuff to avoid people jumping to all sorts of crazy assumptions.
1) The 2nd part of this post is just a rumour. I posted it here because a) I could not be bothered to make a separate Rumours Section post and b) it was relevant in context to the spoiler part
2) They are from the same source
3) Now the fact that the rumour that some of our Losties are on The Black Rock ie Sayid, Locke, Kate, Claire: Does not necessarily mean that they are on The Black Rock back in the 1800's. They could simply being filming a scene inside The Black Rock in current time.
4) The Alpert/MIB scene is on the Black Rock in the 1800's
Thanks to our guy PF108 for the following snippets of the current filming of the Richard Alpert Episode
Ok Dark here is what I know, and it's pretty wild:
-On monday at Diamond head studios, they will be filming Alpert scenes on the Blackrock. There is a mock-up of the BR in front of a giant green screen inside there.
-Actor present during this scene are for Alpert, Father Suarez, Capt. Whitfield, and (and this is what they actually called him) the man in black.
Will keep you posted when I find out more Dark!
PF108
Source: PF108@DarkUFO