16v 50mm inlet info

is there an easy way to identify a 16v 50mm inlet manifold that's still mounted on the engine??
one thing i did notice is there's a triangular cutout above the 'D' in the DOHC badge where the throttle cable holder sits, is that it??

 

The 50mm intake pipes 'get wider' near the spark plugs, the 42s have parallel pipes.

http://gvk.altrezia.com/50mm_top.jpg

Pic too big for the forum.
Edited by: G_V_K

 

50mm has dents around the spark plugs

 

dont the 42mm one have a casting date on the top too???

 

That ugly bumpy bit? - on Corrados yes.

 

yes, that bit

 

Does anyone know where I can get an idle bypass screw for the 50mm inlet ?
Lost mine recently and having touble getting a replacement !