Hi John
Short of looking up the different parts, there are essentially 3 types as far as I know for the Spyder
1 - S1 and S2 pre f/l 1600 has two grills and thin raised strip up the centre
2 - S2 pre f/l 2000 and then all S2 f/l has larger raised section with single grill
3 - VX bulge version
In UK there were no IE or VX version Spyders sold. I believe the bonnets for the Coupe, Spyder and HPE share the same bonnet, but could be mistaken.
Peter