Pictures are always helpful... (and also from the back)
The serial number can pin point the date rather precisely....

For your last question: Yes I think so... and the Heliar alone would probably sell easily...

Wild guess: As seen on Voigtländer Bergheils, the normal lenses for 6.5x9 is 10.5 - and sometimes 13.5; on the 9x12 it is most often 15cm...

What about the more rare Bergheil 10x15? To me it would be possible this lens could be for that camera.. (?)
(If so, there's a special back on it.. hens the question about the back..)

EDIT: found this:

http://www.ebay.co.uk/itm/Excellent-...p2047675.l2557

certainly not for Bergheil...

second edit:

http://camera-wiki.org/wiki/Alpin

scroll down to the 10x15 version...