Managed to trade for an second early style Bosch symmetrical headlight lense. I already had one of these but was missing it's partner.
Now I have two. :)
I'll swap the slightly later hella ones I have on there now out for these period correct ones.
For anyone looking at headlight lenses the style changed substantially throughout the years. It's not something that you really notice until you start looking into it a bit closer.
The earlier style, like these, are symmetrical and have the oval shaped pattern in the center of the lense as well as the 'fluted' pattern in between the vertical patterns of the lense. These style of lenses are known as symmetrical as they do not have the refractors to aim the headlight beam and can therefore be used on both left and right hand drive cars. These are correct for all early cars. There is a similar Hella manufactured version of this lense, which does not have the flutes but is otherwise very similar in appearance. Bosch also made these lenses with the VW emblem on the top-most part of the lense. I believe that those are correct for early split era cars.
From what I can figure out, Asymmetrical lenses were introduced to different markets at different times. I think that the symmetrical lenses are correct up to about 1955 or 56 for RHD markets, at which point the script and lense design changed slightly, with the fluted pattern being removed and the Bosch font changing to a more regular font along with the symmetrical beam deflecting design that refracted the light away from blinding oncoming vehicles. At this point LHD markets still appeared to retain the old symmetrical style lense. It was not until 1960 that LHD markets also appeared to get the asymmetrical lense design. Parts listings for symmetrical and asymmetrical RHD / LHD lenses seem to support this.
As far as which lense is correct for a 356 replica. I think that for the earlier shine down or pre-A style cars these lenses are correct, but for later shine-up cars the asymmetrical lense is more appropriate.