The sump with a thick flange takes a simple rubber seal which fits inside a channel. The sumps with a thinner flange take a composite aluminium and rubber spacer gasket.

http://www.talkmorgan.com/ubbthreads.php/topics/43365/Series_1_Roadster_Sump#Post43365

Scroll all the way down to find the images.

DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4